Hello and welcome to HCM,
Injection of heroin is associated with
tingling sensation in the area where it is injected.
Besides there are symptoms like burning sensation all over the body, dryness of mouth,
anxiety, dilation of pupil leading to
blurred vision, ringing in ears,
constipation, difficulty in urinating, etc.
The symptoms of swelling, hotness and pain around the injection site suggest infection of the injection site.
Using unsterile or used needles can result in these symptoms.
You need to see a doctor for clinical assessment.
In case infection is present, antibiotics will be required.
If not treated in time,
cellulitis and/or sepsis can occur.
Thanks and take care
Dr Shailja P Wahal