Hi Cynthia, unfortunately the scooter might be gone. Leaving it charging isn’t good for it, but probably not the problem. If the scooter was unused for such a long period it’s likely that the battery fully discharged beyond its lower limit which will kill it.
If it’s not powering up / functioning correct after trying to charge, this is my guess as to what happened. You could always try reaching out to Hover and see if they are willing to do anything. The battery probably needs to be replaced.