Seeing as Hive Watchers is the authority on abuse on Hive, and they used to self-vote 60-80 comments a day for $1-2 each it seems it is allowed.
They also earned over $230,000 in author rewards doing things they flagged others for doing for $0.03. So I would think they are the expert authority on it.

But what do I know, I am not paid hundreds of thousands of dollars by the DHF to decide these things.
These are the people protecting you from anyone abusing the reward pool.
RE: Is it okay to upvote your own comments?