Why blisters bite hardest after the walk is done

A blister is rarely a sudden event. It builds quietly over hours: skin rubbing against sock, sock rubbing against boot, dampness softening the outer layers until the friction wins. Heat, sweat and grit all speed the process up, and so does shear — that sideways slide of the foot inside the boot on every step. Many walkers only feel the damage once they stop, when the feet cool, swell slightly and every nerve seems to wake up at once.

That matters because the walk isn't always over when you reach the summit cairn, the last gate or the car. There may still be a road trudge, a train journey or a long drive home. Treating a hot spot the moment you notice it, rather than at the end of the day, is the single most useful habit in foot care.

Clean and cover hot spots early

A hot spot is a patch of tender, reddened skin that hasn't yet filled with fluid. Catch it early and you can often stop it turning into a blister altogether. Stop, take your boots and socks off, and let the feet dry in the air for a few minutes.

Wash your hands before touching broken skin, then rinse the foot with clean water — bottled, boiled and cooled, or a stream you trust. Pat dry with a clean cloth rather than rubbing. Avoid cotton wool, which sheds fibres into the skin.

• Hot spot, no fluid: apply zinc oxide tape or hypoallergenic tape directly to dry, unbroken skin. Smooth it flat with no wrinkles or lifted edges, as a crease will rub worse than the original problem.
• Small intact blister: leave the roof alone and cover it with a hydrocolloid dressing or a non-adherent pad held in place with tape. The intact skin is the best dressing you have.
• Broken blister: clean gently, apply a thin antiseptic cream if you carry it, then cover with a non-adherent dressing. Don't peel away the flap of skin — it protects the raw tissue beneath.

To pop or not to pop

My advice is simple: don't, unless you have to. An intact blister is sterile inside, and piercing it invites infection into a warm, damp, sock-covered environment. There is one common exception — a large, tight, drum-like blister in a weight-bearing spot when you still have miles to walk. In that case, draining it can be the difference between walking out and being carried out.

If you do drain one, do it properly. Clean the area first. Sterilise a needle by passing it through a flame and letting it cool, then pierce the blister at its lower edge, not the middle. Let the fluid drain by gentle pressure, keep the roof of skin in place, then dress it as above. Never drain a blood blister. If the area becomes hot, spreading red, swollen or produces pus, or if you feel feverish, seek medical help — infected feet are not a matter for a sticking plaster and optimism.

Keep walking: padding, tape and lacing

If you must keep going, build a proper cushion. Cut a ring of felt or foam to sit around the blister like a doughnut, so pressure lands on the surrounding skin rather than the sore point. Hold it with tape, and check it hasn't shifted at every stop.

Lacing matters more than most people realise. A heel-lock lacing pattern keeps the foot from sliding forward in the boot, reducing shear across the toes and heel. On long descents, tighten the upper laces a little and consider easing them across the forefoot if your toes are jamming into the front. A boot that shifts with every stride will manufacture blisters no matter how good your socks are.

Socks and boots: the margins that matter

Most blister trouble starts with fit. Boots should hold the heel snugly with a thumb's width of room at the toe, and they should be broken in before a big day out. Socks should be close-fitting, seam-free and made of a wicking material — wool or synthetic blends — never cotton, which holds moisture against the skin.

• Take a spare pair of socks on any long walk and change them at lunch, especially if your feet run damp.
• A thin liner sock under a thicker outer sock can reduce friction between the layers rather than against your skin.
• Trim toenails straight across a few days before a walk, not the night before.
• Tape known trouble spots before you set off, on dry skin, while everything is still comfortable.

Rest stops, overnight care and warning signs

On the hill, treat every stop of more than ten minutes as foot maintenance. Boots and socks off, feet in the air, socks dried or swapped, hot spots checked and re-taped. A little powder or a barrier cream on dry skin can help, but don't apply it to a blister you've just cleaned — keep dressings and creams separate.

Back at the tent, bothy or bunkhouse, wash your feet with cool or lukewarm water and mild soap, dry thoroughly between the toes, and leave them bare for as long as you reasonably can. Elevate them while you eat. Avoid a long hot soak, which swells already angry tissue. Dress blisters fresh before bed and again in the morning.

Expect the next day to be tender, and plan accordingly — a shorter route, softer ground, more frequent stops. Feet that are looked after early will carry you for decades of hills. Feet that are ignored on one long, wet, gritty day can take a fortnight to forgive you.