I’m sorry to read of your mum’s reaction to her myeloma drugs. I presume that you haven’t had a reply because her reaction has been much more extreme than most of us experience, and given we are not medically trained, it’s difficult for us to give useful advice.
I hope that your mum’s health has improved since your post. If you are still worried, I would ring her myeloma nurse and / or the myeloma UK nurse.
It’s not uncommon for patients to have a reaction to lenalidomide initially, this usually gets better after the first cycle- but not a reaction as severe as your mother’s.