Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am very sorry to hear that Elsa's eye looks abnormal to you, appearing to roll under her eyelid and not opening fully.
I suspect that what you are noticing is a raised third eyelid.
The third eyelid is a protective mechanism. It will raise up in response to irritation or pain in the eye or when there is inflammation in the nerve that controls the third eyelid.
In most cases in a young dog the third eyelid raises up secondary to something getting in the eye (like dust or a piece of grass) or some sort of scratch or trauma to the eye. If she tends to stick her head into bushes or has animal friends at home some sort of trauma is the most likely cause.
If she seems fine otherwise and isn't rubbing her eye you can flush her eye with sterile saline copiously and then apply either artificial tears several times a day for the next 24 hours until you can have her examined.
You should also keep her in low light as an eye scratch is painful and feels better in low light.
Do not let her rube her eye. If she is rubbing I recommend placing an elizabethan collar (lampshade) so she cannot rub her eye and further traumatize it.
If her eye looks sunken back into her head, her upper eyelid looks droopy, and her pupil (the circular black area in the middle of her colored iris) looks small in comparison to her other eye then she may have a nerve problem called Horner's syndrome. This can be caused by several things including trauma to the nerve that controls her eyelids and pupil, an ear infection (as the nerve runs by the ear canal and inflammation from an infection can affect it) or idiopathic (which means an unknown cause). If that seems to be the case with her she should see her veterinarian to try and diagnose her problem.
Please let me know if you have any further questions.