I've never tried this, but I've heard that if you take clear nail polish and coat the inside of the band that it will prevent your finger from going black. Acts as a barrier between your skin and the ring.
I've done this in the past and it works. I had some handmade Native American jewelry that was made of nickel silver. Anything with a lot of nickel makes me break out. I carefully painted the inside of the ring and bracelet with clear polish. I as able to wear the pieces with no trouble after that.