Welcome to HCM,
Thanks for posting your query to this forum,
This is because site from blood was taken for investigation there is some leakage of blood in subcutaneous tissue
, usually a firm pressure is applied to check the blood from spreading.
If blood leaks through then some inflammation can occur called thrombophlebitis
it should be mild one and would heal in few days.
This should not be a big issue if you are having pain on movement can take simple analgesic
, and ice fomentation can be done to reduce pain and swelling.
If it is bruised then a heparin
ointment locally would help to clear it fast you can ask your doctor to prescribe it to you.
Dr.Akhilesh Dubey M.D.