I agree with sufficio and others.

The problem is probably dehydration. For a quick, partial fix, put the snake in a clean plastic box with a quarter of an inch (about 5 mm) of water in the bottom. Leave alone for half an hour, so the snake can feel safe enough to drink. If the snake has only been in your possession for a few days, especially if it came from a pet store, it's good to make sure it gets a drink anyway.

Do you know when the snake last shed its skin? If you do not, or if it's been more than 3 days, leave the eyecaps alone. A newbie can do severe damage by messing around with them. I've seen many snakes shed off a retained eyecap in the next shed. There was a documented case of a cobra that built up 7 eyecaps on one eye before they were taken off. And there was no damage to the eye. This was before antivenin, when an accident with a cobra was likely to be fatal.

Good luck.