That looks like an unhealed navel, not an unabsorbed yolk sac. In one of my hatches this spring a chick had an unhealed navel and it was protruding quite a bit. It shrank, scabbed over and healed just fine. I didn't let him go outside until it was healed. Keep the environment clean and dry.
On my chick I didn't use an ointment at all, just kept in a clean, dry environment. Since it's scabbed over, and as long as there's not redness around it the scab, he should be fine without the ointment. It will probably dry up better without ointment also, which is what you want.