Good Afternoon and welcome! I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
From your description, it appears that Bisciut may have injured this area during the night which has caused a neurologic issue. The fact that the eye is drooping and may have lost some sight may mean that he has hit his head causing an interference with the nerve supply to the skin surrounding the eye and/or the eye itself. You have doe the correct thing for now which is to apply drops of Artificial tears that will keep Biscuits eye moist and flush away any irritants or bacteria.
If Biscuit were mine, I would be very uncomfortable leaving him without having his eyes checked. Eye issues can be very serious especially if left untreated,. I would strongly recommend that you take Biscuit to the ER vet so you know for sure that the correct treatment is being given to him. I know this is expensive but I worry very much if you leave this untreated while traveling which could make thing worse. Eye issues can be very sensitive.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please REPLY so I can clarify for you.
Sincerely, XXXXX XXXXX
Thank you so much, Deborah for your kind rating. It is very much appreciated! Do not hesitate to contact me with any other concerns that you may have about Biscuit's eye issue. If you have other questions, please Reply.
Have a great day!!