My dog got stung by some kind of insect and it has like a big bump on his lip and I would like to know if anyone knows if that is dangerous and/or I could give him some medicine

Cats are my experience, but...

Mammal lips are extra sensitive. Bee stings elsewhere go barely noticed, but on the lip significant swelling is typical.

I would watch pooch closely (for odd behavior) over 48 hours from when you first noticed it.

Don't worry if you see him licking at it frequently, but if he acts tired, unfriendly or in pain after 48 hours, I'd take him to the vet.

Hi, megaman,
Sometimes a little Baking Soda, mixed with water, to give a paste, rubbed on the lip, will help.
If it was a bee sting, or even a spider bite, it will help. He/she might lick it off fairly fast, but it might still help. Best of luck.

Keep an eye on him. An external sting isn't too bad, but if he managed to catch and swallow something it may have stung his throat. That can be very serious. Any sign of not eating or trouble breathing calls for immediately getting him to a vet.

Where are you? Stings are usually a summer hazard. Could be a spider bite. They can be very dangerous. If so, he does need to see a vet.