Hmmm I don't know where to put this (tanning question)

So I went tanning for the first time and I got burnt pretty bad :( But now about 5 days after it happened I just noticed today that I have like a brown mark on my stomach that's probably a little less than a centimeter in diameter.

Someone told me that it has something to do with more melanin or something in your skin and it just happens naturally when you get those rays. I think it's really ugly and want it to go away though. Will it ever go away??