<s>[INST] I have a light purple bruise on my bicep and my veins are much more noticable this morning that before. i havent had alot of water today so i am wondering if its just a normal bruise and the veins are unrelated and just due to lack of fluids. or if there is some cause for both? [/INST] Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. Did you hurt your biceps means have you sustained any injury. If no, then while sleeping only bruise in biceps very unlikely. Other causes of bruises are usually due to fragility of small blood vessels. Dehydration has never been mentioned as cause of bruising. Hope I have answered your query. Let me know if I can assist you further. </s>