I have been blackmail someone who I met on...

If you are exposed to blackmail and threats of photos sent to your cell phone application, you have to file a complaint at the Cybercrime Department in the Criminal Investigation Department at the Police Station of the emirate in which you reside
You can provide all information regarding the phone number that sent you threat and extorted you. Print it if possible.  All messages that you have received.
The police will identify and track the accused's number, arrest him and bring him / her to trial
On the other hand, in the case of conviction, the penalty will be  imprisonment and paying a fine, or at least one of the two penalties
Find below the Anti-Cyber Crime Law, related to your inquiry:
Article 16
Whoever blackmails or threatens another person to induce him to do or abstain from doing an act, using a computer network or an information technology means, shall be penalized of imprisonment for a period not exceed two years and a fine not less than two hundred and fifty thousand dirhams and not in excess of five hundred thousand dirhams or either of these two penalties.
Finally, the penalty shall be imprisonment for a period not exceeding ten years if the threat is to commit a felony or to assign matters perverting honor or humanity