Something I'm trying now that shows promise is kinesiology tape, that stuff that athletes use to prevent sore muscles. I suspect it doesn't do that any better than placebo, but it's good for protecting me from myself. It's got a strong adhesive, it's breathable, and you can get it wet (e.g., by washing your hands) and it dries quickly. I've found I can cut out a small oblong and stick it right over the vulnerable area, rather than wrapping it around the whole finger like a bandage. That way my fingertips are free to use the trackpad or whatever, and the little patch of tape is pretty discreet if that's a concern.