Upvote in your own comments is like advertising yourself. I don't even know that you can upvote your own comment. Although I am a new joinee but still I though that it is not the right way. Even in post initialy I though somehow mistakenly I have done upvote on my own post. 
Most probably I have upvote my comment in one post by mistake when went for unchecking it shows error message that I will not get anything if I cancel my upvote. So in fear I quit to revert upvote. 
But I don't know that this is not the right way. 
Thank god for sharing this information with all. 

But I thing I am very stunned how @mindhunter came into the list. I am dam follower of him. I liked his all posts.