I cured a large hematoma on my cats ear with the homeopathic remedy Arnica mont 30. I believe I just gave it once a day, maybe twice. It took about a week to ten days to completely resolved but there was improvement right away which was steady until it resolved. The ear flap returned to normal. In this podcast homeopath Joette Calabrese mentions that in classical homeopathy, Arnica Montana is always used for hematomas. Cost $8.00.
https://joettecalabrese.com/podcast1/podcast-73-my-time-with-the-banerjis/
If it’s gone on for 2 years and you haven’t gotten it addressed in that time, it’s most likely something that REALLY needs a vet’s involvement. Could be medical, could be dental, but you should call the vet about it.