Pics would help. What's your humidity like? It might be a retained eyecap but don't mess with a retained eyecap. If it is an eyecap, you can try soaking to remove it and the rest of the stuck shed, but don't under any circumstances try and remove it yourself. Don't let a vet do it, don't do it yourself. You can blind your snake. If there's only one cap you can wait until the next shed and as long as your humidity is okay it should come off with the one under it.

But pics would definitely help. Also knowing your husbandry (hot side and ambient temps and humidity) can help.