Would denouncing cheaters from an exam make me less likely to receive penalties? I aced my undergrad studies and got the best offer I could ever dream of for grad school.

And three **** might have ruined it.

They ran into me and asked for help with "studying". Turns out it was blatant cheating and I helped them anyway. I had my doubts, but my compassion instinct took ever.

I'm looking forward pursuing an academic career, and I don't think this event was good at all. It's nowhere near loving my sleep over this issue, but I want to keep my academic integrity and cover my ass.

Now, if the punishment for cheating was just a failed exam, I would've denounced without hesitation. But in my country, you can get banned for exams and higher education for 5 years. I think it's enough to destroy someone's life. At the same time, they (the 3 ****) put mine on the line so they could pass some exam. (If they get caught and I somehow get involved, I can get banned for 5 years too. Everything I worked for 3 years, gone in an instant)

I'm about to send the email to the equivalent of the Dean, but I just can't know for sure if I'll stay safe. I know him kinda personally and have friends that are friends with him, but still, I'm scared and I fucked up.

What should I do?

Edit:

Here's a rundown of the events


I ate at school self, not my usual spot
The 3 **** ran into me. They asked me to help them with studying and I accepted. I had doubts that it was a cheating scheme but paid no mind to it.
A few hours later, they send me a photo, there were some questions and I assumed it was an exam from previous years. I asked them when was the exam and they said "now lol". Doubts that it was a cheating scheme were almost confirmed. I answered these questions and sent the answers anyway because I was pressured from holding an unwritten contract and instinctual compassion
They sent another photo, I saw the date of the exam and it was the day all of these events happened. I stopped communications.
And here we are now. I helped them cheat and I want to pursue an academic career. This is like a big stain I'd like to clean.
Talk to someone you can trust.

The rules in your place seem to be very severe. Therefore, I advice you not only to listen to people in this forum, but to consult someone who knows the rules in your country. In my other answer, I recommended ombudswomen/ombudsmen or the student union. As in your country, you can be banned from higher education for 5 years, I would advise you to talk to a lawyer. Let them advise you.

In most places, the best way would be to "confess". However, if in your place it is possible to get punished for five years for what you did (which is in my eyes no misdeed at all, as you did not know you helped cheaters) there may be more messed up rules/strange things going on. So please, for your own sake, consult a lawyer (or similar), good luck!

(And yes, of course consult the institution rules and try to find out if similar cases happend before.)