A year ago I made a decision to convert to Judaism. The final stage in the process is to immerse in a mikveh, or ritual bath. I have several tattoos and piercings, and I was curious about how all this would be handled at the mikveh. The official rule is that all jewelry should be removed. I couldn't find any information about tattoos. I posted a letter on RAB asking for help. A couple people did send some information, that the tattoos shouldn't be a problem. I wrote to a website which has an "Ask the Rabbi" feature, and was also Orthodox -- i.e. quite strict. I asked if I would be permitted in the mikveh with tattoos. The response I received was that anything I did to myself before I converted had no effect, and all they could do was ask that I not get more tattoos. So I felt better about this.I was still concerned about my piercings. Nothing is new, and they are all well-healed. I have both nipples, daith, tragus, nostril, and a couple of outer ear cartilage pierces. I spoke to my piercer and he said he would be happy to remove and reinsert all the jewelry for me. I also investigated the official religious law and discovered that any "loose" jewelry is acceptable -- the main concern is that the water should be able to touch every single part of your body. I decided to remove everything except the nipples (for some reason I am extremely squicked by messing with my nipple jewelry beyond changing beads) and daith (that bugger is quite awkward to get to).
At the actual mikveh, there was an attendant who came in after I got undressed and was immersed in the water. She makes sure that you have completely immersed yourself. She was not staring at my body, and the water was so incredibly cold that I had my arms crossed over my chest, and could barely say the required blessings because my teeth were chattering. (FYI, mikveh water has to have a natural source. This was a natural spring in a mountainside, and I don't think could have been warmer than 12 C.) The attendant did not comment on my tattoos either, so everything was okay.
I am not sure what the rules would be for an Orthodox mikveh (I belong to the Conservative movement, which is a bit more lenient). I am told that often you are "inspected" by the attendant before you immerse at Orthodox mikveh's, so I imagine you might have to remove all your jewelry. According to official law I did not cheat though.
I hope this information will be helpful to any other women (or men) who need to undergo this process and are also pierced and/or inked.