...other than going to someone who would understand (probably not his parents, but maybe either Sadie, or the Gems, or Lars in his own body) and explained what happened and tried to figure out how to fix it ASAP?

And even if for some reason that wasn't an option and he HAD to keep it a secret, it's really not appropriate to like, make grand love confessions to someone under the guise of being someone else.

Of course he meant well, and I don't think he's a terrible person (quite the opposite!) but he did really fuck that one up, and I wish he'd been shown to learn from it a little more.