Dear Jordan:

Thank you for your question. 

The Church teaches that we are to confess in kind and number. That means that we are to confess the kind of sin and the number of times we committed the sin (if known). We do not need to go into details unless those details are pertinent to the sin.

For example, if I shoplift at Walmart, Target, and Penny's, my confession is, "I shoplifted three times." Mention of the specific stores is not necessary.

On the other hand, if we leave out pertinent information, then we have a problem. For example, the story is told about a man who confessed stealing a rope. The next week he confessed again the stealing of a rope. And again the third week the man confessed stealing a rope.

Finally, the priest asked, "What is it with this rope?"

The man replied, "The rope was attached to a cow."

The rope was not the whole story, as what this man had actually done was to steal a rope and steal a cow.

In your specific case confessing blasphemy is not enough, in my personal opinion. There are many ways to commit blasphemy. Most often it would be presumed to saying God's name in vain. Thus, I think that we need to identify the kind of blasphemy.

Using the story above confessing blasphemy is the rope, but the rope is attached to the specific blasphemy against God and our Blessed Mother, improper use of blessed object, and improper use of a prayer.

Thus, in my opinion, you ought to go back to confession and confess masturbation while saying the rosary.

We are praying for you.

God Bless,
Bro. Ignatius Mary