Healing issue with Rapier 2

[CRose801]

This is the 3rd black and grey tattoo come back with this on it... all three have been long healed (over a month). These spots are not going away. It almost seems like a rash on and under the skin, its real dry and flaky but doesn't seem to hurt the client... 2 of the tattoos that came back with this were on large leg tattoos... 5 hour + sessions, the 3rd was on a stomach... Any idea on how to get rid of these spots and what is causing them?? This is the first time seeing this in 5 year of tattooing and they have all happened in the last 3 months or so...