theme not visible

hi
so i tried to install the theme.
it obviously didn’t work because it’s not in the theme list.
but when i search for pictorico it says ‘installed’ so i can’t install it again.
how do i uninstall it so i can reinstall it and activate it?
presumably that is the the only way to get it to come up?

been going round in circles getting more and more infuriated.