I frequently ride an '84 Centurion that I crashed in 1996. Frame was straightened and there is a VERY slight bulge on the bottom side of the downtube near the head lug. There is no sign of cracked paint near the bulge. The bike has thousands of miles since that crash.

Is your bike safe? I'd take it to a shop for further inspection. Definately treat the cracked paint and check for any rust.