Thanks for choosing health care magic for posting your query.
I have gone through your question in detail and I can understand what you are going through.
generally develops when there is trauma. If it is occuring without trauma then it is a matter of worry. It suggests that you have bleeding tendency and then you should do bleeding time
and clotting time.
Mostly it will come normal and there is no need to worry.
Hope I am able to answer your concerns.
If you have any further query, I would be glad to help you.
In future if you wish to contact me directly, you can use the below mentioned link:
Wish you good health,
Dr. Srikanth Reddy M.D.