How do you beat vlad as riven, i swear its impossible.

Just about every other melee champ in the game can ask that about Riven

Oh, riven, the most op champion, has 1 counter? Deal with it, it's your punishment for taking advantage of riven and make life a hell for every top lane champion.

Some lane match ups you aren't going to win, it's more of a question of how even can you keep it and how you can help your team in other ways. If you get counter picked don't look for solo kills look for opportunities to teleport or roam to impact other lanes. Do your best to freeze the lane by your tower and wait for a gank.

Get a gank from your jungler.

Seriously, once you get slightly ahead and have a Hydra you can pretty much all-in him at any point and out-sustain him.

Vlad is just one of those champions. It's so easy to escape, the only way you're going to get kills is if he lets you. Basically take ignite, and wait for him to be overly aggresive, or extended enough for a gank. Vlad starts with sustain, and most vlads rush so their sustain will always be really high. Basically a Vlad player isn't going to die unless he wants to start making risks. All you can really do is try to punish him when he does take those risks. You want to try and get an early advantage before he gets too spellvamp crazy, so try to punish his earliest mistakes. Otherwise after that, Vlad won't die unless he wants to, so roaming is the only real option if you wish to try and snowball, or are now behind and easily zoned from farm.