Rash and fever while breastfeeding

Patient: Last night i felt itch.it feltmy body and faceespecially nose, ears, and neck.These part is hot.so l have a fever.It’s hard to endure itch.I have a 6 month babyso I’m breastfeeding.How can l do for it?Can i take a Benadryl cream?i have it.Tell me that asap plz!