Although there may be various reasons for skin discoloration in that area, it is best to get it handled immediately by a professional medical practitioner. As you seem to have tried various creams for the same, it may be due to some underlying cause that is not apparent unless it is actually checked in person by a doctor.
Patches like this in the region you describe are sometimes an indicator of Inflammatory Breast Cancer (IBC). Breast cancer is detected by the presence of lumps in the breast, which can often be felt in a manual breast examination. IBC however is not indicated by the presence of lumps. Although there are no discernible lumps there are patches of red, inflamed-looking skin that look like an infectious rash. It is accompanied by a sense of warmth in the skin.
On the other hand, if the rash has a warty appearance or it looks like slightly raised skin with small bumps on it, it could also be an indicator of seborrheic keratosis. As opposed to IBC, this is a non-cancerous growth and will not lead to any cancer. You can safely leave it alone unless you wish to remove it for cosmetic reasons.
answered by G R