Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am sorry that you have been waiting for a response, but your requested expert isn't online which delayed your question coming up on the list for all to answer. I would like to help if you are still interested in an opinion.
I understand that you are concerned about looking silly when your fellow Nicholas's' symptoms seem to be coming and going, especially when he is preoccupied with something else. Dogs with chronic discomfort can be distracted, but if he is still hesitant to open his eye that tells me it is not properly healed.
It sounds like he was diagnosed with some corneal scratches/abrasions and although he is a little better after medication he still isn't opening his eye normally. That tells me he is still painful, and that the lesions probably didn't heal. That isn't normal as most heal very quickly, but it does happen, especially in dogs with poor tear production or large, prominent eyes. Corneal ulcers/scratches that don't heal normally and quickly as usual are called indolent ulcers. There are indications that this may be an indolent ulcer.
If we stain his eye and examine it closely we will see flaps of corneal tissue at the edges of the ulcer rather than a sharp edge that indicate an ulcer that may have trouble healing, or the ulcer may be deep or larger than normal, or he may have blood vessels forming on the cornea indicating the ulcer isn't a simple one.
With an indolent ulcer the best chance we have of getting it to heal properly as quickly as possible is to debride the lesion and then protect the ulcer with a temporary third eyelid flap or a soft contact lens.
If we don't treat indolent corneal ulcers aggressively they can turn into a melting corneal ulcer and the eye can rupture.
In some cases dogs have to have an even more aggressive surgery called a conjunctival flap to treat indolent ulcers and save the pup's vision.
I think that your pup should be rechecked. Please don't think this is a waste of time, something definitely isn't right with his symptoms.
Another option is trying more medications from his veterinarian such as oral nonsteroidal anti-inflammatories for pain and inflammation, antibiotic eye medications to prevent secondary infections and eye drops with hyaluronic acid to help protect the eye while it is healing and keep it moist. He should be rechecked in 5 days and if the ulcer isn't gone or almost cleared then you can decide to go ahead with more aggressive therapy at that time.
I think that a visit to your family veterinarian is best as soon as possible.
Please let me know if you have any further questions.