Robert

Here's what I would do:

First cut out all of the rotten wood....get down to the clear center wood. Then I would cut into the cambium all around the edge of the wound....so as to have some green showing......all around. Then I would apply new cut paste........then I'd re-check it each year in the winter, and re-cut the cambium each time, (showing some green), and then re-apply the cut paste again.You do it in the winter in order to "catch the vigorous spring growth each year".
It is the cambium, from the green material, that the healing will grow. I think azaleas are rather fast, so it shouldn't take more than a few years for the full healing to take place.
.......but, personally, I'm not bothered by a scar, (shari) on the trunk....but it should definitely NOT contain any rotting material.
Good luck, and I hope this is useful information.

Robert......in Sta.Cruz

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Robert.........in Sta.Cruz