high humidity and temps are the foundation to bud rot (botritis).
get a humidistat and dehumidifier in addition to a thermostat and fans/air conditioning.
try to keep humidity under 50% at all times during flowering. this is key.

Also, flowering for 52 days is less than 7 1/2 weeks. unless its some amazing strain that finishes super early, try letting it go 8-9 weeks after you fix your temp/humidity issues.
GanjaRobPDX Reviewed by GanjaRobPDX on . High Humidity, High Temps & Bud Rot.... This pic shows what appears to be a healthy plant.... However upon closer review, you can see some leaves that have somewhat discolored....that's where you know the Bud is starting to Rot.... With some rubber gloves and needle nose scissors, you bend and find the bud rot and cut it out.... 2-3grams worth of plant material was removed.... Rating: 5