Hematomahttps://en.wikipedia.org/wiki/Hematoma
Hematoma is localized bleeding outside of blood vessels, caused by disease or trauma such as injury or surgery, and may involve ongoing seepage of blood from damaged capillaries. It should not be confused with hemangioma, which is an abnormal growth of blood vessels in the skin or internal organs.

A collection of blood (or a hemorrhage) can be aggravated by anticoagulant medication (blood thinner). Blood seepage may occur if heparin is administered intramuscularly.

☆ AI Dermatology — Free Service
In the 2022 Stiftung Warentest results from Germany, consumer satisfaction with ModelDerm was only slightly lower than with paid telemedicine consultations.
  • Upper Arm Bruise
  • In this case, people are often concerned about melanoma. If it occurs suddenly within a few days, it is usually not melanoma. If it develops slowly over several months, melanoma should be suspected.
  • Blood donation ― Bruise
  • Unlike melanoma, these lesions are pushed out at a rate of 1 mm per month.
  • Development of intramuscular hematoma
  • Hematoma on the backside
  • Subungual hematoma
  • Bruising
  • Plateletpheresis hematoma