Hello,

Thank you for asking your query at DoctorSpring.

It seems you are having a prolonged local reaction following an anabolic steroid injection. A mild reaction is common, as you have already experienced. This appears to be prolonged and most common reason is a body reaction to component in the new injection. (not to the steroid components, but to the additives). The concern here is about the purity and trustworthiness of the brand of injection you got. Like whether it is immune safe ? Pure without contamination ? etc. I assume the needle used for the injection is fresh and sterile.

For now you should rest the arm, and elevate it slightly using a pillow while sleeping. Do not workout or exert. Take a OTC anti-inflammatory medication like Ibuprofen 400mg twice daily in consult with your Doctor. You can apply ice or cold compress over the muscle couple of times a day. If you have itching you can take an anti allergy medication. Drink plenty of water.
I recommend caution and getting touch with your Doctor if the symptoms persists or worsens with these measures in next 24 hours. Ordinarily a local reaction can be observed, but in your case as I said before there is a possibility of contamination and hence some extra precaution is needed. But do not worry much. Hopefully this will resolve by its own soon.

Hope this helps
Please feel free to ask followup questions.
Thank you
PS : I hope you are aware that steroid injections are harmful to your body in long term.