Braces and Retainer

I had braces a while ago and I seldomly wore my retainer. My first retainer didn't fit well anymore so I got a new impression and a second retainer. Now that retainer doesn't fit anymore. It does fit but it doesn't go all the way in (touches the roof of my mouth)

If I keep wearing this retainer, will it eventually fit again? Also, I have a tooth that has shifted slightly out of place forward and my bottom teeth, although are not shifted, are getting kind of tight.

Should I get a third impression and get a new retainer? Is it bad to wear the retainer I have now?

[Nurse Ratched, RN]

We're definitely not a dental board :). Please call your dentist/orthodontist.