I've had 2 tats done as a Christian, and hope to get a couple more eventually. i have no conviction over them at all. I've seen lots of Christians with tattoos and some with a lot of tattoos.
My thought is if you feel convicted, don't do it. If your conscience is clear then go for it. The above scripture says nothing about tattoos. People who use that often use it to support their own Opinions, but rarely do they ever apply it entirely throughout every aspect of their lives. It's only given when it suits them. I've yet to meet a single person who thinks it applies to other areas of their life or body when it might make them have to change.
But as far as any tats you have already, i don't see God convicting you of something already done, that can't be changed and was possibly done a while ago. Unless these are recent and since becoming a Christian then the conviction may be in your head. That said, i'd still stop and reconsider and pray before thinking about any more.