Suggest Remedy For Mild Bruises In Scrotum Of Infants

My 5 month old son's scrotum has small visible blood vessels and appears generally purplish. I have been monitoring it for about a month wondering if maybe his car seat or jogging stroller had caused it to maybe get pinched what appeared to be minor bruising. It has not improved so I have ruled this out as being the cause. He does not appear to have discomfort. He is happy, smiley and bubbly. He does occasionally tug on this side when he is in the tub but has only just started doing this. Should I be concerned?