Try gently putting the retainer back in your mouth: if you have to force it, then it no longer fits and you should not try to put it in your mouth. Contact your orthodontist for a visit: you may need to get the retainer adjusted, or get a new retainer.2020-11-06
Can I change the shape of my retainer?
Plastic retainers can also change shape if they're handled incorrectly. For example, using the front wire as a handle to put the retainer in and take it out can cause the retainer to bend, wherein it won't fit correctly. A retainer can also change shape when it's slept on or accidentally stepped on.2017-03-20