So he's acting normally, but just has those spots? If so, I wouldn't worry about it yet. I would do a partial water change, to lower the level of wastes or bacteria in the water. This will help prevent infection, in case the spots are from wounds.
If the spots don't go away by tomorrow, OR if they start to look worse at any time, OR if he develops new spots -- please let us know. (If that happens, please also fill out the info on this sticky
so that we have more information.)
But for right now, I'd just do a partial water change, and keep an eye on him.