I had my right snakebite redone right through the old hole. The only issues I had were that it took a little extra oomph for my piercer to get the needle through (I believe her exact words were "Holy scar tissue batman!" lol). It didn't hurt, but the pop as it came out the other side was a little weird. And then for about a year the jewelery would occasionally hit the scar tissue that had been pushed to one side inside the healing hole and it would hurt. Not real bad, but it wasn't pleasant either. After that year the hurt went away and I've not had any issues with it. You can't tell it's not the original piercing either, it doesn't look like it was redone or anything. I've also had my labret redone twice (tho I don't have it now) and always through the same spot as well. The only thing was the extra force to push the needle through the scar tissue.
~*~*~Don't let today's moment forsake tomorrow's dream~*~*~