Is this a reset?

You shouldn't reset your pmo counter.
I daubt if you commited a sin and even if then it's not a deadly sin. Why? because in order to commit a deadly sin we must give our full consent to the sin. In your case you didn't give your full consent because you actually stopped your actions before you'd watched porn. Lack of full consent of our will to a sin makes the sin a venial one and this is the official teaching of Catholic Church.

Venial sins as you know are forgiven by God in general confession at the beginning of each Mass and they are burned in Communion. It's even possible that you didn't commit any sin - as a pmo addict it's hardly to say if you give full consent to pmo sins. In order to give a full consent we must have full freedom of our will and we know that if we had a full freedom of our will we wouldn't be addicts but free people.

That's why drug, alkohol, pmo ...etc addicts can take Communion even if they took a drug, drank far too much or watched porn or masturbated provided they fight their addiction and struggle to get rid of it. If they gave up and aren't struggling then they commit deadly sin(s) and they mustn't take Communion until the time they'll go to confession plus they'll start fighting this addiction again.
So say many Catholic priests in my country who I talked about with addictions. (I asked some of them even during confession).
Ask your priest about this.

Although you didn't commit a deadly sin or even maybe no sin, you did something extremely risky opening the porn site. You feel for sure that that story could have finished with your full pmo act(s).
You simply made a typical mistake I had done countless times until the time I discovered a remedy which I have been using successfully till now. But this is another story which I described in my method.

 

The second practical indication that you didn't commit a deadly sin or maybe no sin is your state of hesitation - If we commit a deadly sin our conscience knows it simply without hesitation. One priest told me a practical wisdom (having learned it from his regular old confessor) - if you hesitate in your conscience if you commited a sin or not then it means you hadn't commited the sin because to commit a sin we must have full awareness that it is a sin and if you hesitate then where is your full awareness of the sin???
All in all appologise to Jesus in your private prayer and ask Him to give you forgiveness for your lack of prudence and the state of addiction which you allowed and ask Him for His help and the gift of enlightment what you should do in future similar situations and for the power to overcome it. After this go forward and foget the event. It's no use living in the past.

What's the use of a pmo counter? Thousands of addicts of this and other sites glorify their personal counter as if it was something most important. but it isn't. the counter says only how many days you didn't commit the sin (at least as outer acts) but what with our mind? phantasy? we can commit plenty of sexual sins or other ones in our head. We cannot focuse our attention on avoiding sins but on seeking the presence of God and doing what He says by His word and Church teaching. Our sinful sexual acts (pmo) come from our mind (heart) so they won't stop if we don't change our mind (heart). How to change our mind? (it's called metanoia) We aren't able to it but God is. He changes our mind(heart) when we are in His presence (prayer, Mass, Communion...etc.). We MUST attack the source of our sins (our mind, heart) the rest is only the results of our thoughts and sick feeling (for example pmo).
Most addicts resemble a man who is trying to extinquish the fire by pouring water on the flames ( they hard try not to do pmo and endure one day more so that the counter could reach its success) but each fire fighter knows where he must pour water - not on the flames but on the kindling, burning material which is the source of all the flames. The kindling is our sick mind, soul. The water is the Holy Spirit, Spirit of Jesus Who heals our mind, heart, soul provided we are in His presence (prayer, Mass....).

To win this fight and not only this we must be like professional fire fighters.