Brief Answer: Hot compress should work. Detailed Answer: Hi, Welcome to Healthcare Magic! You are right in saying that it usually takes a few days for the pus to form and come out from the head of the swelling. In your case, as it happened within hours, it is most likely the exudate produced due to the immediate chemical reaction to injection of an irritant (e.g. heroin) which stimulates an inflammatory reaction. This inflammatory reaction usually resolves in a few days. But if there is infection, an abscess usually begins to develop three to ten days after the injection and slowly grows in size and discomfort over the following week. Presently, you must apply hot compress to the site frequently. This will increase the blood supply to the area and hasten the drainage of the exudate. This will also relieve pain. Elevate the leg above the level of the heart, to improve drainage from the site. Take a paracetamol (tylenol) if the pain is too much. Keep the area clean. Then make arrangements to see a doctor as soon as possible. A course of antibiotics may be needed. Whether an ambulance is needed or not would depend on whether the swelling subsides or not with the hot compresses and how bad you are feeling. Hope you get well soon. Take care. Best wishes. Dr Preeti Parakh MD Psychiatry

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