2nd the entropion thought.......have a google for in turned eyelid in lambs. We’ve had it a couple of times and on both occasions have managed to turn the lid with no veterinary assistance. Pop it out and then smooth back as if wiping something from your eye. If done immediately it can sort itself straight away, left, as with yours it will probably take a few attempts - as in a number of times a day. Fingers crossed for you