So far, I haven't had any problems with that. When I first started cupping my neck, I was a little bit worried about that, so I was very careful. I thought it might make me dizzy, or lightheaded, but it doesn't seem to. I've even cupped right on my throat and I haven't had any problems. It's a bit uncomfortable but it's really helped loosen up my neck.

I have had a few cups that bled a little bit. I think that's usually if there some type of a blemish on my skin. Maybe a small scab, or mole, or something like that. When I pulled the cup off, the bleeding stopped right away though.