No worries. Under normal conditions the creeks are small & easily crossed.
There are a few bridges too en route.
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 Alpamayo are the tiny black flies that pestered us at some campsites. The bite is not painful but the welts get infected causing itching for weeks afterward!
Mosquitoes are sometimes a problem though we saw few in September.
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. You can buy it in Huaraz or bring it from home.
Damage to gear on pack animals
If you do hire pack animals, protect your pack by covering it with a large burlap rice sack. (This also makes it difficult for curious fingers to open small side pockets.)
You can buy rice sacks in the central market in Huaraz. Make sure it is large enough to swallow your whole pack.