I was careful not let any paint get insie by putting a masking tape over the outlet oppening. After I finished painting I removed the tape and put the cover back on. Now I don't have any power from this outlet anymore. What could go wrong and what should I do?
Van

First check the breaker or fuse for this circuit. If they are OK then reopen the receptacle and use test leads to check on power coming into the box. Becareful because you may not have power from the receptacle but you may still have a hot wire in the box. I suspect your black/hot or your white/neutral came loose. Are they attached by screws or back stabbed

I'd recommend doing the following at the same time as checking the breaker, but before looking at the wires.

Does the plug have a button on it that says 'reset'? If so, then push it. You could have tripped or push the test button on the GFCI by mistake

And if that is not a GFI, It may be on the Load side of a GFI Receptacle?