Blood clots and the medicine to resolve them, suck.
They are very scary.
I had one a few years ago after having broken my ankle and essentially immobilized myself while it healed.
Anyways...mucho pain and they found the clot. Spent a while on blood thinners and getting stuck to draw blood a couple of times a week. It finally dissolved and went away. But it's a scary ordeal.
Prayers for your mom for healing.