Hi there
@temporaryforever
I was gonna welcome you, but now I'm seeing you've been lurking around a little while. Either way, we can get you sorted out.
Firstly, some substances are just more caustic than others. Cocaine and Methamphetamine are especially well-known culprits for producing injection complications. A complication is more or less defined as an issue arising from an injection that does not resolve on its own in a relatively short period of time. What is par for the course following a missed injection, is about 48-72 hours of irritation and mild swelling, with a feeling of heat emanating from the injection site.
It should start to resolve within 24 hours, be getting a lot better by the 48 hour mark and should be difficult to notice by the 72 hours mark. I'm not a doctor, obviously, this is all from personal experience. The 48 hour mark is when you should be watching. If it's getting better, you've got nothing to worry about. If it's not getting better or getting worse, you're probably gonna need medical attention to be completely safe (it's likely to become a chronic infection i,e, abscess).
I generally do a warm, damp compress for 15-20 minutes at a time. The warmth stimulates movement and blood flow. It should also help with discomfort. In between warm compresses, you can feel free to use ice, but this is exclusively a treatment for the pain. You can feel free to use some OTC analgesics, as they really do help.
If it doesn't start getting better i.e. less red, less painful, less "hot", then either come back to us or go to the ER or urgent care. They can hopefully help you treat the infection without having to come back and get it lanced. If you have any questions, we're here.