Hi @chaosninja ! :)
Thanks for coming to Spotify Community! :)
Since you mentioned logging into a musician website, it may be that you authorized a plug-in app in doing so. My first suggestion is to check your account page and see if you gave any artist or music label authorization to your account.
You can find this on the sidebar under "Apps" (screenshot).
If you recognize anything you don't want to have access, just click the Revoke Access button.
If you don't see that this is the case, there is a guide here on what steps to take if your account has been compromised.
I hope this was helpful and have a wonderful day! :)