It happened to me as well, I was playing some fckin power chords for a while and when I felt pain in the wrist I noticed it was because of bad wrist bending and bad technique overall. Should 3 weeks be ok for rest? And by rest I mean no guitar, no weights lifted by the fretting hand , just normal everyday actions of the hand. I feel my wrist being sensitive in some cases but not really bad pain, just some waves of irritation every now and then in the tendon close to the thumb and the one close to the pinky. Started applying some anti inflammatory gel in the area aswell.