mastitis? or something else?

I have had a sore breast and nipple for a week now. Sunday I noticed a quarter size raise red mark and lump next to my nipple. I went to my regular MD and he put me on a antibiotic and said I have an infection in my glands (mastitis ). (I am 60 and a type 2 diabetic (under control) My sister and mother had breast cancer.)  I had a mamo and MRI (history in family) on my breast 5 months ago, and everything was fine.

Should I wait to see what happens for a week or 2, or should I see a breast specialist? Or am I being overly concerned about this.
Thanks you, RS

[Cleveland Clinic]

Dear BobbieJP:  Given the recent negative mammogram and MRI (which is a very sensitive test), it seems reasonable to wait at least a week to give an antibiotic a chance.  If this gets worse or does not improve, you should go back to your doctor or seek another opinion with a breast specialist.