Undiagnosed rash for 5 years. Please can anyone help? (Photo)

It is under the breasts. It occured within 3 weeks of silicone implants but a breast specialist said it is impossible to be related. I am not convinced. It does not itch, however I am aware of it. It has a purple tinge to it after bathing. It has also at times appeared on shoulders and upper back. I sweat profously and have had ink blue stains on t shirts underarm area. I don't use deodarant or chemicals. I have lost muscle in shoulders and hips (proximal).generally unwell and fatigued.