is this bud rot? and if so can i still dry and smoke the rest of the plant?

From a harm reduction standpoint the whole plant should be tossed.

It is bud rot. It is highly recommended to throw all plants exposed to spores away. It is not a cut around, and throw out bad parts thing. Bud rot spores can make you extremely ill. Plus you can't see them.

probably... cut around it.. give an extra wide berth. even if you can't see it, you likely have spores elsewhere on the plant. it'll be there when you smoke it too. i won't tell you what to do, but you can make a decisions based on reality rather than how most lie to themselves about such things -- like "bud washing" cleaning WPM, LOL .. nope, it doesn't clean anything, lol. it takes solid particles off like dust but does not competently remove mildew or mold etc from plant material. still smoking wpm... like i said, cut it out with a wide berth. if it's all you got, you live with it. probably cough a bit more. maybe cough up soem plegm in morning more than normal. i had bud rot outside once. i cut around it each small infection. it looked clean.. did not smoke clean. i threw it out. each to their own.

As long as you don't smoke the moldy bits the other bit should be OK but watch it as can cause serious health problems with moldy buds happy growing

From my point of view, yes, on these rainy days with a lot of humidity, it seems like mold. Sometimes you can't see it well, but it's inside the flower. Or there could be pests in the soil; there are spots on the leaves, which is one of the signs. Pests that feed on the roots, in an advanced state, cause the plant to die every day. When I had a pest like that, my leaves turned yellow and died. Your leaves aren't at that point. That's why I'm leaning more towards mold.

Yes it is and yes jjst get rid of the bad buds and the buds that are close to them. The rest will be fine.