sorry but thats funny. Theres always the potential for damage in such cases due to different voltages going through different "pins" But i wouldnt think that one boot would be an issue unless the psu is really screwed up.
reminds me of the time I bent an am2 pin and broke it off. I have build alot of pc's, and these things do happen.
If it does damage Just RMA it and dont elaborate on the cause. Just say blank boot screen or something.