Preserving a plate with chocolate

Hi there- I’m very clueless and not even sure if this is the right product or forum but.. my fiancé proposed to me with a dessert plate and it says will you marry me written in hard chocolate. It’s a very hard chocolate and it’s been a few months of sitting on the counter and it’s solid on there. But I’d like to learn how I could preserve this?? Any advice would be so appreciated!