From what I understand, you can get an allergic reaction to the dye- 4 years later, I'm not sure if that is what is happening, but I suppose it could be possible. Here's a post that one of our doctors answered that had similar symptoms to yours-
https://
www.medhelp.org/posts/Dermatology/Burning-sensation-in-healed-tattoo/show/675909
It's always best to consult your doctor and let them know that the cream didn't work. Also, some fungal infections can be a pain to get rid of, so it's possible that even if the cream didn't work, that could be the root cause of the issue still.
Give your doctor a call, let them know you are still having symptoms, and let us know how you are doing! Get better soon!