Preschool Behavior and Repentance

When Spencer went back to school after Christmas break he started coming home from school sad on a daily basis. When I would ask him why he was sad he would say, "I got in trouble 5 times today," or "I got in trouble 3 times today," you get the point. When I asked him if he was sitting in time out, he said no, his teacher had just said that he need to sit down, stop talking, etc.--you know "reminders" of good behavior. So I told him every day he didn't get in trouble he could have a treat when he got home. So for 2 weeks or so he got in the car and would say, "Mom, today was the best day EVER!!", meaning he didn't get in trouble. So anyways, I said that since he was doing so great, now he needed to go 5 days in a row before he could get a treat.
So yesterday would have been the big 5 day mark. Spencer got in the car, and sure enough-BEST DAY EVER MOM! Then about 30 seconds after we pulled out of the parking lot he proceeded to tell me that another boy was using bad words so he did too, but it was okay because they didn't get caught (at least he was born with a little bit of a sense of guilt). I told him that we would have to wait another day to try for the treat, and he very dramatically explained that it wasn't his idea, he couldn't help it--and my personal favorite, "IT WASN'T MY PLAN!!!" I laughed so hard (to myself).
This morning we were saying prayers before he left for school, and it went something like this, "Dear Heavenly Father, please help me to have the best day of school ever, and not use bad words like bottom, in the name of Jesus Christ, Amen." (I guess we can now determine what the bad words he had used the day before were). When I picked him up I said, "Spence, was it THE BEST DAY EVER?", and he told me it was, except for one bad word. He then said, but it's okay because I said a prayer to God. I asked him if he was repenting for saying bad words, he said yes, and so you wouldn't be mad at me, and then "Do I still get a treat since I said a prayer about it?" Now how can you deny a repentant 5 year old--especially when he just proved he did listen in Family Home Evening!!!