I used to have a bleeding wrist when I played with a pick, and when I was a very sweaty teenager, basically from the friction created between my very sweaty wrist as it rubbed against the bass as I picked up and down very hard and fast. The first time it happened it really freaked me out, but after that I just got used to it and thought it looked "rock 'n' roll" until I grew up.
(no offence but....)
If you're playing fingerstyle and you get that much friction/abrasion between your wrist and the bass, then your wrist is far too sweaty!! A wrist band could help I suppose, or long sleeve tops, but I hate wearing sleeves to play. Talcom powder could also help, or whatever it is that weight lifters use to put on their hands. You need something to dry your wrist out a bit, and something to ease the friction a bit.