I'm going to ask for a higher pay even though I already agreed to a lower one. I hope it works, what do you think will happen?
Why did you accept a lower pay?
I justified it by considerations that did not convince me.
You have to honor the agreements that you make. Next time, you should consider carefully before accepting any offers. If you rush into negotiations, you might make a decision you regret later.
Tell me about it, that's one of my problems.
Asking for higher pay probably won't work out for you since you did agree to the lower rate. You need to honor your word and work hard so you can earn a pay raise.