I wrote an answer to a similar question recently: Brijesh Kumar's answer to Why are there so many racist comments by Indians in Quora?
Indian people are not “polished.” They don’t know what to say to whom and when to say it. Most people are very simple and they don’t know very sophisticated speech. They would say what comes to their mind. Some people have better “filters” because their society is trained in such a manner.
The reason people from other parts on India make fun of people from North East India is because, in India or may be in the whole world, “Small eyes and thick eyelids are considered undesirable.” Most people in the west would not make fun of Asian people because they are “polished”, but they do consider it undesirable. You would never see a white person, get plastic surgery to get eyes like Chinese/Korean/Japanese people. Moreover, in recent years, lakhs of Chinese women are getting eye surgery every year to make their eyelids thinner and eyes bigger. So, even some Chinese people consider such eyes undesirable. I find this trend to be very unsettling because they get serious medical problems in such procedures. I watched a documentary where a woman could not close her eyes fully after the surgery and both her eyes would close to varying degrees. She was unable to sleep at night because she could not close her eyes and they would pain when she tried to close them. She was miserable. I felt so bad for her that she destroyed her eyes and happiness for the sake of beauty.
I feel, it is better to have a known enemy than an unknown one. I would much rather know what the other person is feeling than to guess what his intentions are. So, don’t worry about it too much. Most of the people say something as a matter of harmless fun. It does not really mean much. Throughout my childhood, I was called “Takla” (bald) because I had (and continue to have) less hair and “Mote” (fatty) because I was fat. But, I don’t think any harm was meant. One of my aunts is called “kallo” (dark girl) because she is dark in complexion. Her mother calls her that. My uncle was called “kalu” (dark boy) because he was dark in complexion. They don’t mean much. It is just some harmless fun.
As long as there are people, there will be prejudices. If not because of your eyes, they will find something else to make fun of. As long as it is harmless fun, I don’t think there is anything to worry about or take it too personally. Most Indian people are not “polished”. Please cut them some slack.
PS: Bullying and physical violence are obviously outside the purview of “harmless fun” and has to be dealt with seriously by the government. I am seriously against the plastic surgeries. Women (and men) have gone crazy to appeal to ever changing standards of beauty and are destroying their bodies and psyches in the process through these plastic surgeries. Once they have plastic surgery, they are never satisfied and they keep on going to the plastic surgeon. It is an addiction. Like we have our monthly barber’s visits, they have monthly plastic surgeon visits.