I just deleted all accounts that haven’t been accessed at all. If you were unlucky and made an account while I was doing this, recreate your account again.
Also installed captcha and anti-spam modules, so you shouldn’t see any more spam on the site. If you do, report it (should be a link below the comment), but I haven’t seen this module let anything through just yet.
EDIT: Turned the captcha modules off, turns out it was causing more problems than it solved.