dogfaced puffer and posable ick?

[luv4scjjt]

I have a dofaced puffer who one day show's what look like the spots for ick then the next day the spots will be gone or in a new spot. Do ick spots go away overnight? None of my other fish have signs. Or could this just be fine grain sand sticking to his slime coat? Please help me so i can either continue treating for ick or relax. I have been stresing over this guy for a week,. He does eat and seem fine just the spots show up and go away and so on.