How much damage? We can never know - not exactly - but I have been experimenting with my meter.
I already knew that potato elevates my readings for a long time - but now I know that anything I could not eat and lose weight also jacks up BG. I was going to try a few more things, but have decided against it - I saw my grandmother dying from the complications of diabetes when I was a child and it was dreadful.
Rejecting the standard versions of foods is probably seen as you blaming your mother for feeding you her versions - maybe not even consciously, hence her anger and all the huffing. It is a lot to do on your own - but perhaps you need to have a really serious talk with your mother and tell her just what you are risking if you did eat carbs. Point out, gently, that there are so many options which you can eat without risking your sight or your feet.