Helo and welcome to HCM
The bite on the arm has caused a hematoma
formation which is responsible for the bruising.
The associated swelling is also due to same reason.
Human bite can also be dangerous as human mouth has anaerobic bacteria. So it is advicable to get a tetanus toxoid
if the bite is severe as in your case.
And do visit a doctor as your bite is not a casual bite. It has caused lot of injury
Thanks and take care
Dr Shailja P Wahal