The sublabial suture can certainly be removed in the future but my advice at this point would be to sit tight for now. 5 weeks is verrrry early in the healing process. Much of the changes you're seeing right now might be related to swelling in the area. Photos would be helpful to give you a better answer.
It is unusual to hear of having an alar cinch all by itself. Yes, it is possible to simply remove the suture. If you have absolutely decided to have this reversed, the sooner you do it, the more likely your tissues will go back to where they were beforehand. There may be some residual scar tissue created during the process, but hopefully your body did not react much to the permanent suture.