Don't do anything with it until it has cooled down. Then run cold water on the lid or put some water and ice on the lid to get it nice and cool. finally you are going to have to break the air lock that has formed so gently slide a thin spatula or similar blade under the lid to let some air in.
If you were able to put the cover on in a reverse fasion than that means to me that it is quite worn at the catches. You may want to continue in the wrong direction with extra force and it may pop off. However I would strongly advise against using this p-cooker until you replace the cover gasket.
Answers & Comments
Don't do anything with it until it has cooled down. Then run cold water on the lid or put some water and ice on the lid to get it nice and cool. finally you are going to have to break the air lock that has formed so gently slide a thin spatula or similar blade under the lid to let some air in.
If you were able to put the cover on in a reverse fasion than that means to me that it is quite worn at the catches. You may want to continue in the wrong direction with extra force and it may pop off. However I would strongly advise against using this p-cooker until you replace the cover gasket.