Blue spot on my leg. Anything to worry?

Hi sir/mam, I'm sikha age 30 yrs from karnal working in an IT firm in ggn, on this weekend I travelled to Vaishno devi and completed the whole sight by walking only, just for your information sir/ mam, I don't do any exercise, after a very long time I have done so much physical activities..may be this could be a reason of my problem....so my problem is, the vry nxt day whn I came back to karnal frm vaishno devi, there are several blue spots in my legs, however this blue sopts were be visible earlier as well, but this time the intense of blue color is more....I don't knw the exact reason for this problem and Please suggest what actually this problem is...nd anything to worry ? Thanks in advance, shikha