My boyfriends mother doesn't like me. What do I do?

I find most situations like this are the result of not knowing or assuming what other feel. Did she tell you she does not like you?... and if so why? you cannot fix or adjust what you do not know.

Maybe you can try talking to the mother? Try to make amends with her or spend some time with her

You not need to do anything! Be just yourself, not need that everyone would like you or love you. Just be respectful and don't worry