Sorry, tattoos in general are a crap shoot at best, little ones like that especially cause they just wind up generating randomly. If this was a pony model I'd say put tattoo in your negative...but flux doesn't have that(I've heard there's something you can do in Comfy for negative prompting but never tried it.) That said I just tried a few different prompts in Forge to see if I could get them to stop appearing and so far "she doesn't have any tattoos" at the end of my prompt has worked the best but definitely isn't perfect.