reaction to tattoo

I have 4 tattoos and got them over 15 years. The tattoo I have on my back breaks out in raised lumps under it similar to hives but not ichy or sore. Why does this happen?? My mother got one of her tattoos at the same time as me and her's does that too. Is it the body rejecting the ink or type of ink???? Is there different types of ink???????

Its photo toxicity...fairly common ...no worries.