My 24 Yr. Old Daughter Has A Red Rash Under

My 24 yr. old daughter has a red rash under her arm near her breast and below her arm pit. This is day 3 of the rash and it has grown in size each day...tonight is looks like a red heart, no bumps, all one color. She has a fever of 101 since yesterday and has body aches. She went to the doctor yesterday and was given a 5 day antibiotic. Went back today and was told it might be shingles (rash is not consistant with shingles) or meningitus (told to go to ER if fever increases). Meanwhile, the dr. prescribed an anti-virial med. and took blood to test for Lymes. Your thoughts?