tattooing over my scar

I got a tattoo of a kiss on my butt last april, and I loved it the artist did such a great job and I loved showing if off. I was told to use A&D lotion on it for the after care. I was unaware that I was actually slightly allergic to the cream so I broke out from it. Eventually it all cleared up and then about four months later I got a huge cyst right next to the tattoo that is now a small scar. I know its from the lotion because I have never had anything like that anywhere on my body until I used the lotion. I have heard that you should wait at least a year before tattooing over the scar. I want some more information because its like a big insecurity for me now and my bottom used to be my favorite part of my body lol. I want it hidden so bad but I dont want to cause more damage.. HELP! lol