What kind of over-rev engine damage possible?

I have a 2002 Toyota Celica GT (not GTS) with 99k miles. There has always been a slight ticking sound under the hood since I got it (it had 70k miles), the ticking gets faster with RPM, and is much louder when the engine is in cold start, but quiets down when warmed up, but still audible. Recently I got into a race on the highway and accidentally slammed it into second gear rather than 4th, and the tachometer flew far over the 8000RPM max, Id have to say I hit about 10500 RPM... now that same ticking sound is much louder, coming from same side of engine, and there is a vibrating metal sound coming from the same area. The engine still performs and accelerates the same, but the sound worries me. My oil level is almost to the minimum level (since I havent gotten to change it yet) but just wondering what exactly the sound could be? everybody is saying it is probably a valve lifter? Toyota shops charge $167 diagnosis fee...and I dont have that much money for them to just look at the car and not do anything... Thank you for the help!