'Space blanket', band-aids (lots and both the good fabric ones and the plastic one), water purification supplies (a filter, bleach, whatever), a spare compass, a spare knife, a couple disposable razor blades (or better yet a few disposable scalpel blades), a small hand-full of 18 or 20 gauge hypodermic needles (just the needles, not the whole syringe)-pick these up at a farm supply place (these are absolutely the best things for picking-out slivers and little thorns, they are streile and very sharp, not just pointy-sharp; but if you have a really close look at the tip, you'll see that there are also very tiny 'knife edges' which actually make the point), two tubes of topical anesthetic, make one tube something like 'Lanacane' in a big tube, which is moderately effective for stuff like itches and sunburn, and one tube of something like 'Emla' which is very effective and expensive and can actually be used to numb a small area for minor surgery. a tube of some sort of anti-bacterial, like 'Polysporin', a tube of petroleum jelly, some extra sunblock, extra mosquito repellent, an 'esmache' bandage, a couple triangular bandages, a couple rolls of gauze, and a couple of pressure bandages.
Oh, and toss in some tape suitable for direct use on skin, something like 'Transpore', 'Medipore' or 'Dermafix', some black electrician's tape and some duct tape, plus some safety pins.
Plus pack a few of the really large plastic garbage bags, the orange ones that are used for leaves and other yard waste. These make bivvy bags, raingear, or a body bag, if you are really feeling poorly.