I have varicose veins . one week before a purple/blue patch appeared on my right leg/calf. now its diminishing and pink in colour. what is the reason.

Burst vein: It is possible that your varicose vein made some small capillary vein fragile and burst open, and curse the discoloration, that the body eventually absorbed the blood and start diminishing in size.

Bleeding V V: Sounds as if you may have had an area of the vein that may have bled under the skin leading to the formation of a "black and blue" mark which is similar to what can occur from an injury. See a vein specialist for an evaluation of your veins.