Don’t know what’s wrong with my rabbits ewr

by Zena
(Israel heifa. )

My rabbit has been scratching the top of his ear only and his fur seems sticking to itself and crusty I noticed a big spot in his ear when I wiped it with a cloth dipped in warm water it started leaking clear liquid and it now looks like it’s healing but id like to know what's wrong with him .
Can please anyone help to try and know what’s wrong with his ear ?