Soreness with vulva cancer!

I’m desperate for help for my grandma. She has just finished radiotherapy on a squamous cell carcinoma on her vagina. She is so sore to the point she can’t even sit down. Can anyone recommend a cream or coping method to make her more comfortable? She has tried instillagel vagisil barrier creams for incontinence. She’s currently on morphine and it’s not helping. She’s just so sore and uncomfortable, has anyone got any success stories? Did radio help and how long did it take? Thank you x