My Mom Started Pylera Thursday Afternoon And Today Showed Me

My mom started Pylera Thursday afternoon and today showed me a growing rash she has on her upper left abdomen. It covers a pretty large area (6"x8") and appears to me spreading out and around her ribs. The timing of the rash make me think that it could be related to the medicine. She is also undergoing chemotherapy for Stage 4 breast cancer, but this rash is new. The rash looks slightly raised and itches occasionally. I plan to call her gastro doc next. Any thoughts? Do we go to hospital when she wakes from her nap of wait for doctor's advice first. Thank you.