White mold on Bud surface

It’s likely more to be WPM than actual full on mold or bud rot. Look up bud washes online. You can disinfect your bud after harvest so it’s safe to smoke.. loses some flavor and terps but if the inside of the bud isn’t browning and dying it doesn’t sound like bud rot.

Hi fellow grower, you are more likely to get your question answered if you attach your diary to the question. Along with some pictures of the problem. Makes it easier to diagnose issues. I wish I could help you but without seeing the issue, I don't know what the problem is. Good luck and happy growing