Thanks for clarifying your question. Phrased this way, it sounds like the answer you are looking for might take a little soul searching, to figure out why it makes you uncomfortable to look at someone who is unattractive or unusual looking. Part of that is normal psychology, because the long long period in which human behavior evolved disfigurement could be a sign of disease, and people who responded negatively to an odd appearance in a stranger might have avoided contracting dangerous diseases. It's a common issue with leprosy in parts of the world where it still occurs frequently. People are literally outcast from their homes and villages, and in communities where little is known about how the disease is transmitted, it probably helps limit its transmission. Of course, these days there is a treatment that will stop transmission, though the damage to the nervous system cannot be repaired and the secondary infections that cause those who have had leprosy to lose limbs are still possible due to untreated injuries they cannot feel.
On a social level, there is a purely antisocial kind of response based on our reaction to what we perceive as different or alien that can turn into outright discrimination, and if your reaction to a person's appearance prevents you from respecting his or her basic humanity, or getting to know them as a person, then you may be inclined to social prejudice. There are a lot of other reasons for feeling discomfort, though, like heightened empathy, in which case you project what you see in others upon your self, and this can feel like a threat to your own identity and make you uncomfortable. In other cases, what you feel might just be an instinctive reaction to an experience that challenges your perceived norms and the feeling serves to make sure you don't take the situation for granted. Again, a lingering survival trait in which different can be dangerous.
So, to answer your question, there isn't an "okay" or "not okay" type of answer. It's more of a "food for thought" type of situation.
