Scab in inner ear

Ticks or flies.. More likely a tick cause that.
You need to feel around the insides of his ears (as in rub) and make sure theres no more ticks in either ear. You can feel them (ticks) if they are there. But sometimes they can get way down in the ear canal.. And check his tail also.. And between back legs is another spot they like.

I’m guessing it was a tick. Also make sure to check under his mane, and behind his ears. That’s were they like to get mine at.

Agree that one looks like a tick bite, but gnats will also get in the ears and leave bumps. If you can check the ears every day and wipe them🤠

You pretty much have to check every inch of a horse, when it comes to ticks, incliding their anal area their private parts, the fold in the sheath if you have a gelding, crest of the neck, armpits — everywhere.

They are nasty little creatures.

Some type of bug most likely but plaques are possible and irritated by bugs.

Luna gets that stuff in her ears often. They are always caused by ticks and after I pick them off, the scabby stuff stay there for a long time. Nothing to worry about in my opinion, unless it starts emerging pus or lots of blood or something like that.

I spray some fly spray in my hand more toward the fingertips and then rub the entire ear inside and exterior on my horses to keep creepy-crawlies away a bit better. Swat I also use and rub inside and out....

Anyplace on the body where fold of skin occur is a inviting place for ticks and insects to gather and find protection.
Also check carefully the back part of the hoof where that so soft hair is...I've found many a tick looking to set up house and dig-in/burrow in that area too.
Edges around chestnuts too as again, soft entry point and easy access is so inviting.
If your horse has leg feathers...check them carefully so you not miss them.
🐴...

Large animal Vet Tech here: I’d get a fly mask with ears and put SWAT on the backs of his ears before putting on the mask. If bugs keep getting at that wound while it’s healing, the horse could start rubbing his ear on everything he can and potentially cause an aural hematoma. And as the others said, make sure to check down in his ears to ensure no other creepy crawlers or wounds are present. If it seems like it’s not getting better, or even spreads, go to your vet because it could be fungal. Though the photos you provided do remind me of a tick bite. Hard to say just through photos though.