How do I keep Mom from sticking her hands in her diaper after a BM?

I am so frustrated I just don't know what to do ---She does not do it every time --But when I go in to change her and it is all over her hands covers and at times even on her face ---I just feel like giving up ----I know she has dementia/alzheimers but when I walk into that I just feel so angry and frustrated and exhausted she is a bi-lateral amputee so onesies are not an option its hard enough to get her to turn to put a diaper on her.