Don’t worry about forgetting to vote. Anyone could make that mistake and you are not obliged to vote when you comment.
I appreciate your honesty in confessing that it was a simple mistake rather than going into denial as you will see from the behavior of another commentor above.
Have a look at the commenter who denied everything above. Maybe you can give him guidance?
I have given you a vote now.
OK.. Thank you. I'll do just that