Wear comfortable, broken-in footwear. If you feel a hot spot, stop & take off your boots. Put your feet into cold water when you get the chance to cool them.
Wicking inner socks may help prevent blisters.
Bring Leukoplast or Elastoplast bandages, duct tape & any other blister first aid products you like, just in case.
If you do get a blister, using a sterile needle, prick the blister a few times. Drain without touching the fluid or holes. Seal with liquid Betadine and, when dry, place some tape over it. We usually use duct tape it's inexpensive and seems to stay as well as anything else.
Insect Bites & Stings?
Perhaps the biggest problem on Glacier are mosquitoes at some campsites. Less often you may suffer from flies.
Prevention is the best strategy.
Bring long pants and a long-sleeved shirt. Tuck pants into your socks and shirt into pants. One of our hikers swears by his unlined nylon pants & cycling jacket. Wear gloves.
Insect repellent containing DEET might help a little.
Mosquitoes are worst in June & July. (One reason we hiked The Circle in September!) Park workers told us they saw no mosquitoes after September 1st.
Ticks?
So far as we know, ticks live in Glacier. But Lyme disease has not been reported (so far). Check for them after walking through shrubs and high grasses.
Ticks are tiny and may go undetected. Be attentive. The tick must remain on your skin for 24 hours or more before there is any risk of disease transfer.
The bite is often painful and may result in a slow-healing ulcer.