All you did was paint your tail lights right? Meaning, you just un-bolted the necessary bolts, twisted off the bulbs, and then painted right? After you got done painting, you put your tail lights back on, in the reverse order? As stated above try swapping out your bulbs. If that fails... How did you check your fuses? Pulled them out and eye balled them? Or did you have that mini-fuse test light thing? If you have, or can get access to a digital multi meter, that would be perfect.
--- Even though your fuse LOOKS to be good, that doesnt necessarily mean it is. Best way to check is with a DMM ---