Afraid not, except that this is how my breast cancer was first detected (clearly not the case here). I simply got a sore breast (didn't find a lump) and it looked like mastitis or an abscess. My lymphoedema is in my left arm, not my breast (I had a seroma on the breast site post surgery, which may have contributed). Any infection in a lymphoedemic part of the body may need antibiotics, as the body's own capacity to deal with even a minor infection in that part of the body is reduced - so the prescription for antibiotics makes sense, as does time for the infection to clear.
Perhaps give it another week then seek another opinion? What does your lymphoedema therapist say?