This seems to be a fault in the design of the website. When you hide a question, the record of the question disappears also from your profile. There appears to be no way for you to reshow the question.
I shall ask Super Administrator Einstein to look into this to see if anything can be done.
In the meantime, all Admins and Moderators can see a list of hidden content - comments, answers and questions - by all users. So you will need to ask an Admin or Moderator to reshow the hidden content.
You can also ask for content which is not your own to be reshown by an Admin or Moderator. This might be because you think the hidden content is useful.
See also I have encountered a difficulty with the website. Who should I contact for help?