Is it possible to pray for that grace yourself through the rosary?
absolutely. that is part of sanctification. Pray for an increase in Grace. I recommend that you pray for the grace to grow in the virtue of Hope.
Have Hope. Remember that the Gospel is called THE GOOD NEWS. Why is it called the Good News? Because God has done all the heavy lifting and made it easy for you. At a minimum, you say the Morning Offering and the Act of contrition. About 30 seconds each. You go to confession and just list your sins:
1. I gossiped about my best friend behind her back (always popular with the ladies).
2. I was a few minutes late giving my husband his nightly foot massage.
3. I nagged my husband about 35 times.
4. One time I let the beer run out.
That takes about 30 seconds. Then you keep quiet and LISTEN. Don't clarify, explain, or give the priest your theories. 99.5% of the time the priest is not going to ask for clarification because he has heard the sins 10,000 times before. You do your penance and you are forgiven. Why are you forgiven? Because the priest said you are forgiven, and your opinion in the matter doesn't count. You then go to Communion. Why? Because the Church says you are forgiven, so you can go.
That's it. And you are saved. Sounds like Good News to me. Now I recommend also working on Sanctification and deepening Charity, as this has eternal rewards in Heaven, but let's stick to the basics for now.
Scruples also has a tinge of pride in it, so pray for the grace to grow in humility. And go schedule an appointment with a priest and tell him you have scruples, because you have scruples.