Of course you dress up bro - do you want to look like you're a cheap dick who doesn't care?
Or do you want to look like a respectable guy who at the very least gets his clothes cleaned, and brushes his teeth?
... try walking into a nice restaurant wearing torn shorts, beach sandals, and a dirty t-shirt ...
... then come back the next day in a suit, and see if you get different service.
Sure, you'll get served both times
and the food will taste the same
but I'll bet you the experience is different. It's worth the small investment of effort and forethought.
No, you don't need to get your teeth polished, she won't reject you if you didn't cut your hair this month (or longer), and don't go spending on expensive outfits or flashy bling. She would very much prefer your dollars to end up in HER top drawer, not lining the pockets of superwealthy shareholders of expensive branded luxury stores. So go as you are.
But you owe yourself the respect to look your best, as you are today. When people who see you THINK you feel like king of the street, the way you actually feel inside somehow doesn't matter quite as much as it did before.
And after you've banged a few good-looking and sexy girls
And they've said "come back soon"
You might find yourself feeling better about yourself