>>1229825A tiny FAK is good and useful. Some medical tape, gauze (or duck tape + super glue) anti-bacterial gel, antihistamines just in case, and maybe advil if you want. Put it in a little plastic ziploc or something.
I also bring eye drops, chapstick with spf, small thing of salt for leeches, tweezers for ticks/splinters, waterproof gear tape (for tents, tarps, shells) and antacids but not sure if you'd consider those first aid. Not all 100% necessary, but definitely all useful.
Weighs well under a half pound, and if you get injured, you can be a bit more comfortable.
Sliced my foot open on a zebra muscle on day 2 of a 5 day portage trip. Some anti-bacterial gel, gauze, and tape helped keep the sand/mud/crap out of it and allowed me to be much more comfortable on the portages. I wouldn't have died, but re-opening/embiggening the wound, possibility of infection, sand/literal shit getting inside; all not fun. I wear basically sandals because you hop in and out of water/walk rivers up to waist and boots would be useless.