Ok so I went and performed an ethnic cleansing (genocide) in riften and now I cant go back into the city
wut do guise, wut do?

Go to jail or pay a bounty

The guards dont respond to my yield

You may have to kill a few more

Choices and consequences, that's what people want in rpg's. Be a man and finish what you started.

IT WASN'T MY FAULT
I KILLED A DB TARGET AND THE GUARDS WENT APE [censored] AND BLOCKED ALL THE EXITS
IT WAS A CLUSTER[censored] IN THE BAR

What did you expect? You're a mass murderer, of course they want to take you down.

Try fleeing to another hold and waiting several days. The guards might calm down in the meantime, maybe you'll be able to talk to them and go to jail.

You could reload a previous save perhaps? After a certain bounty threshold they kill you on sight I think, yield won't help. When it happened to me in Markarth I had to load an old save from before reaching the city because I had no idea why they were shooting me. Must have been a damn chicken that saw one of my blood rampages.

[if pc] godmode, profit.

Bull, you can always get through/run away. You chose not to, chose to stand and slaughter. Anyway... give it time. Stay away from Riften (and the Rift, if needed) for a week or so. When you go back, svck it up and take it like a man... or dish it out like a maniac, either way. But you can't rightly expect that people in a given city/hold will ignore your presence after killing 15 of them, with witnesses.