Why is my cockatiel gray around the face?
If you look them up, you will see many of them have this.
I would just watch him closely. If he’s acting happy my guess is he’s okay? Check with your vet if you’re really concerned - I once freaked out that my bird had orange on his face, thought he was bleeding. Then realized he was rubbing his face on his toys!
What did the Veterinarian say? You can't be too concerned if you haven't asked one.