Blotchy skin on my back

My girlfriend recently noticed a bruise like patch on my lower back. It has been over a month and it's still there. I would think it was a birthmark but she says it's got a blueish undertone and I don't remember it being there before. I've had back problems for the past 3 years. So I'm wondering could this just be a permanent bruise from my over tensed muscles pushing on the skin?

[Bhupinder Kaur, MD]

Hello,
Your symptoms are suggestive of seborrheic keratosis(a non-cancerous benign skin growth that originate in keratinocytes and like liver spots, are seen more often as people age),solar lentigo(dark (hyperpigmented) lesion caused by natural or artificial ultraviolet (UV) light),birth mark or pigmented naevi or melanoma(chances are rare).

I feel that an examination by a dermatologist will be the best. Without examination,it is very difficult to say anything. Hope it helped. Take care and pls do keep me posted on how you are doing and if you have any additional queries.