It is either heat damage or Mold. If your lights are a good distance away (18 or so inches) and you have good airflow - It is mold. Both can look similar. Break open the bud and see if it is brown underneath. If it is - cut it off and do not use it. Throw it away. You might as well do this in either case. Mold induced pneumonia can scar and ruin yours or a friends lungs permanently. If its not mold - you need to cool it down with a fan and backing the lights up. I really hope this helps - I know it hurts to throw it out but better safe than on an oxygen bottle.
No....Stop....Don't.... breaking it open will release spores everywhere.. place a plastic bag over the plant and remove from garden.. sanitize garden and start over... :0)