I have a small rash on the outer side of my breast. since it gets no better, do i have ibc?

Probably not: This does not sound like the typical presentation for inflammatory breast cancer. If this does not get better within 2 weeks, i recommend you see your primary doctor or gynecologist. It is impossible to evaluate a rash without evaluating it in-person.

Rare, but possible.: First, start with a visit to your dermatologist. If there is any indication this might be inflammatory breast cancer or paget's disease of nipple, a biopsy will allow the diagnosis to be made. Otherwise, this may simply need an antifungal ointment--sounds like tinea corporis. Eczema is also possible. Examination by a doctor is essential. So make an appointment! best wishes!