My cat has a sore?

For thee days straight my 1 year old hasn't stopped meowing. He was meowing like he wanted me to pet him, so I did but he didn't stop meowing. Then I went down to feed him, but he wouldn't eat. So I cleaned his water bowl and filled it up with water, he didn't drink it. He just kept on meowing like there's no tomorrow!

Just yesterday, I was cleaning him up and brushing his fur, when I noticed his upper lip had a little cut on it and it was a little swollen. Now it's a little dark red dot ( it looks like a sore).

I'm seriously worried! Any ideas of what it might be? 

PS: I'm not in my greatest financial state , I need to know if this is important enough for me to take him to the vet. 

Since he's not been eating, I'd say this definitely warrants a trip to the vet.  Anything that causes a change in behavior, eating habits, or litter box habits is cause for concern and needs to be checked by a vet.

I just want to be sure, since it's not clear from you post.  Are you saying he has not eaten or drank anything for three days now as well? Or just that he has been meowing all that time and would not eat or drink on the first day? Is he using the litterbox as normal?  Is he neutered? Is he indoor only or indoor outdoor?

Either way, the combination of things you've described does merit a vet visit, for sure.  The only thing your answers will influence is whether this is a SERIOUS emergency, or merely urgent.  

I am very sorry you are going through this with your kitty.  I know how scaring and frustrating it can be, especially when money is tight.  However, he does need a vet.

Actually he's eating fine and everything its just that at that time he didn't eat at that time when he first started meowing. Yes he is neutered, and he is using the litter box normally. 

He's mainly an indoor cat but I let him out every once in a while. He doesn't get into any fights though, because hes pretty big and fluffy so he scares the other cats away haha

It is really frustrating, but I'll manage

Here are a few pictures of him 

Aw! <3