Exercise is Not Punishment!
Exercise would be rewarding and relaxing, not a punishment for a dietary indiscretion.
You slipped up and ate two packs of Reese’s Cups. Now you are sitting there trying to figure out how many minutes of running or walking you would have to do to burn it off. Forget about it. I am not saying not to exercise but what I am saying is you need to quit treating exercise like a punishment and food or snacks like something you have to earn with good behavior. Guilt and regret are not positive feelings that will lead to successful weight maintenance.
You slipped up and instead of panicking over how many calories you just consumed, relax and make a plan not to do it again. Putting yourself under stress or regret will only compound the problem. If you exercise, do it to reduce stress and enjoy the activity. Don’t be obsessed over burning away a single snack or meal, rather enjoy the time you are exercising. You have plenty of other days to make up for the indiscretion. Focus on the future and not the past because a small change repeated over and over again can make a huge difference long term.