no that doesnt look like bud rot they are actually very small to have bud rot imo bud rot usually develops later in flowering when buds get dense. what is your humidity like?
Walmart sells cheap thermometer/hydrometer. Bud rot comes in later stages when buds are much more full and only if there is humidity or precipitation. Ps I would defoliate bottom 1/3 off plant. I made that mistake recently.
humidity sensors are cheap buying one small unit would not make you technical and high humidity can cause big problems later in flowering just do yourself a favor and buy one
Depending on what light u have it's most likely going to be larfy airy buds. Also it helps with air movement and also when u water sometime it will go on the leaves. Not always but that can cause pathogens on ur leaves. Also it pushes the plants resources to the colas/top of plant which is going to have the best flowers.