This is a lumbrical which is giving you some shit (little muscle connecting the bits of tendon which do ring and pinky flexion after they have bifurcated - they come off the same tendon). If you ping one fully it will hurt like fuck and you wont be able to take anything with your pinky dropped for ages. So, for now dont climb anything with your pinky dropped - ie. front 3 drags or mid two pockets. Everything else will be fine. Stretch fingers gently for a bit and massage palm etc.
Once its settled down, get a fingerboard and hang front three/mid two on good holds with your pinky curled inwards. Ie do what has been aggravating it but very very gently and in a controlled way. Do this a few times a week. Then gradually over months ramp it up until you are able to pull like fuck on mid two with pinky curled up. Go too fast and 'ping!'.