Byron Kennedy's now had three days to stew over returning a $500,000 ball to Tom Brady ... but he tells TMZ Sports he STILL has no regrets about handing over the pigskin.
We got the Tampa Bay Bucs superfan on Wednesday ... and he made it clear, he's not feeling down in the dumps one bit about giving away TB12's 600th TD ball on Sunday -- even after half a week to think about his decision.
"I think I did the right thing," Kennedy said. "I'm happy Tom has it."
As we previously reported, Mike Evans accidentally gave away the Brady ball to Kennedy following his touchdown catch against the Chicago Bears .