Hello, going by your history, the differentials include lymphangitis and bruises..Lymphangitis just presents with a painful linear streaking on the extremities..Bruises on the other hand, present in various forms depending on the extravasation of blood, a prior history of noticeable trauma isnot essential for it, even trivial trauma can lead to bruising in individuals depending on the age and blood parameters. I would adv you to visit a dermatologist for evaluation and appropriate management accordingly Thank you Take care