I can't leave the Beta, my skins and previous worlds aren't saved.

I was on normal bedrock, Minecraft said I had to update in order to use Realms. I updated only to find that I was now in the beta. It said that another account on my device has joined the beta, which I did under that account, and that updates may include beta versions. But when I log in on my non-beta account it's still on the beta, and uninstalling and reinstalling isn't working. All of previous worlds are gone and so are my skins. I don't know what to do.