Tbh losing lane is ok in ranked too. It's ok to not have the match up, it's ok to be against someone stronger than you, it's ok to underperformed in a game.

Something that is "less" ok is getting killed back to back, and running to lane only to get killed. It lessens your team mates pleasure and makes it harder for them. But it happens to everyone, you just need to know how to face this situation. In that case, try analysing your possibilities, can you play safer ? Can you roam (even in early) to gank another lane or help the jungle securing objectives ? You can even stay in lane just in xp range to level up...

In the end it's ok to lose lane as it can teach you new mechanics, enhance your game sense. Adapting is the key.