Dear Sister,
I am terribly sorry to hear of your struggles with your mother. I must admit that I am quite confused with a lot of the details in your inquiry. You indicate that you started living with your parents at the age of 10+, though you do not share details of why you didn't live with them prior to that and more importantly, where and with whom you did live. Furthermore, I am wondering if your parents are still together. You indicated that your mother came to "spend some time" with you, though you don't indicate how long she has been with you and how much longer she intends to stay.
Your mother has no business beating or biting you at all. You say that you don't talk to your husband about your issues with her and I am not sure why you do not allow him the opportunity to support you as you struggle to deal with your mother.
It is really important that you make a fair assessment of your behaviors towards your mother and that you realize that you are not purposefully wronging her. Because there are so many gaps in your inquiry, it is difficult for me to assess anything about the nature of why this is going on and to judge whether she may be suffering from a cognitive or emotional issue.
In Islam you are supposed to respect your parents and treat them well; however, they are not free to abuse you in any way that they please. There are boundaries to what is acceptable and what isn't. I encourage you to speak with your husband and maybe your father to gain some support. If this continues to be a problem, you may want to gain some mental health counseling in which you can do individual or family therapy.
I pray that Allah will help you gain some peace of mind.
