Puffers are prone to ich but I am not sure what it is. Hopefully someone else will know. Could he have rubbed up against something ... or got stuck in a rock?
Sorry, hope he gets better.
*180 gal Display, 100 gal basement sump, 33 gal refugium, 3x250 MH, 2x160 VHO actinics, zoos, some softies, LPS & lots of acros and other SPS.
*100 gal prop tank plumbed into main system w/ 2x96 PC lights and 1x150 MH,