Light purple/brownish overlying skin of lipoma

Patient: The overlying skin of a lipoma could be red or a little purple, like a light bruise?I ask because I have 4 lumps under the skin of my lower back, and the skin over those looks like a very light bruise (light purple/ brownish).I have had an ultrasound and the doctor told me that looks like lipomas.The lumps are a little hard and doesn’t move too much. The sizes of all are below 1cm.