Hi! Yesterday I found out that one of the buds was...

Sadly yes, rot. Try removing all traces of it from your living plant, in the areas where you found this bud. After that, wash your hands thoroughly and look for any other sites that may also be mouldy and if so remove those buds too. Always wash your hands again if you find some more before touching anywhere else to look further. You may have to increase air movement in your tent to reduce the humidity as much as possible. If you have caught this early enough, the rest of your flowers should still continue maturing as normal. Tell tale signs that there may be some rot in your buds is that the leaves associated with that bud will have died or look as though they are dying and in worst case scenarios, branches will fall over/break, due to the mould eating all the way through to the stems. Also caterpillars can sometimes burrow into the rotten buds, so look out for these too. After looking through your diary, I noticed a lot of burnt leaves, too many nutrients I would say, and these burnt/damaged leaves show signs of mould "attack". Another thing, 70% humidity or levels that high at any time is going to cause mould problems. Cannabis is not a rain forest plant and really doesn't need any auxiliary humidifiers in an enclosed grow space. Switch it off ASAP, your plant won't mind, plus you will save money. Hope this helps,.... Organoman.