Most ACUVUE® lenses either come with an 1-2-3 inside-out mark or an AV inside-out mark.  This helps you to determine whether or not your lens is inside out. How it works:

123 inside-out mark

Put your ACUVUE® lens on your finger and look at the lens from the side. You should see the 1-2-3 written correctly. If the lens is inside out, the 1-2-3 will appear reversed.

 

av inside-out mark

The AV mark works in a similar way: If you place your lens on your finger and look at it from the side, you should be able to see the AV written correctly. If the lens is inside out, the AV will appear reversed.