I don't hear any distortion, but i'm very angry about how stupidly i handled it and concerned there are some frequency changes because of the dents, don't know if i should try the tape method or just leave it, didn't know this plastic is so very thin and bendable with even a soft touch.

I tested on many left right, different frequencies and bass heavy videos on youtube and on higher volume, didn't notice any unusual sound or change yet.

Thanks for reply, how to notice a change in sound? so far i don't hear rattle or buzzing for example, can double sided tape help to undent it without removing the cover?