This can really put people off, especially if you have a meeting coming up or want to look "fresh". I've read that it's not to be confused with the effects of smoke - the cause is in the blood vessels, not the irritation from the cigarette. To quickly "sleep" red eyes, you can use vasoconstrictor drops, or even a cold compress for a couple of minutes to reduce swelling. You can check out this explanation here: https://unitedrecoveryproject.com/rehab-blog/high-eyes/ - it has information about triggers, duration, and methods for relieving the condition. Water also helps - cannabis can cause mild dehydration, and that in itself increases dryness and redness. If you're interested, I read an article where everything is explained well - how this effect occurs and how to slightly reduce it.