You might try some nice warm compresses and see if that helps bring down the swelling. You can put some Epsom salt into some warm water soak a washcloth wring so it's not dripping and place over the swelling. I'd keep using the Terramycin.
Is the swelling hard or fluid-filled?
But if you don't...
Are you still using the Terramycin? Any discharge coming from the eye or nares? is a vet an option? Hear any congestion?
If it's an abscess a vet would be best.