If, as an editor, you want to act as an reviewer as well, I suggest that you create a separate user account with the reviewer role and use that. As you can see, OJS does not handle the situation you described all that well. Edit: just like @gail suggested!
See Editor as well as reviewer with trouble reading other reviewers' reviews and Editor stuck in reviewer role, OJS3
You can still access the editor view of that submission. Open any other article and go to the review stage. Look at the structure of the url there. The number in the url is the submision id. Replace that number with the submission id of the submission you have trouble accessing as an editor.