Seeing the location of it, I don't think it will affect your tattoo. But, saying that, everyone is different. The artist that did my side piece said this " Think of the skin as a rubber band when you write on it, then stretch it, it is larger. Write on it while stretched, then let it back to it's normal state, it will be smaller".
My experience with tattoos and weight have been different. After my side piece I maintained weight, then due to life and choices I gained weight, so yes it appears larger, and I now have lighter stretch marks running through. But, as I'm losing it is getting smaller.
I think if it changes your ink at all, it may appear smaller if anything.