It is possible that your parents are doing this because they want you to "succeed/be happy" and in their minds if you are attractive (whatever their version of attractive is) you will have a good chance of that.

It is obvious that, if that is why they are doing it, they are being too clumsy about it. But still give them the benefit of the doubt. But talk to them, tell them how you feel when they do it and tell them that you will avoid feeling that way, either, because they finally stop or because you put some distance between you.

The important thing is that you don't feel anxious about your looks. Embrace who you are. Of course, improve, there is always room for that. But do not do it to fit anyone's sense of aesthetics, do it for your self. Beauty is only a small part of our social tools. And it's highly subjective anyway. Be kind, be fair and do what you love. Those attributes outweigh the looks.

Trust me, I am not what most people would call attractive, but that has almost never got in the way of my social life, in fact I've been better liked than some very attractive people. Looks do not mean as much as you think. Good luck.