Does your clarinet look like this? I hope not! But even if you just need a minor repair, get it done! You will play your best on an instrument that is working properly.
When a key is out of alignment (especially the Left-hand B key!), we often compensate by pressing the key down too hard, using the wrong fingering, or over-blowing to get the note out. This will surely create bad habits!
So, get your clarinet repaired! It's very important to go to an experienced repair person who knows how to PLAY the clarinet as well as repair it. Instrument repair is an ART and should be done by someone who is qualified.
For info on qualified repair technicians in the Sharon, MA or Concord, MA areas, contact me firstname.lastname@example.org.