When you allocate Focused Gaze, Blood Burst’s text within the skill tree will update as if the Total Damage Modified, +50% Acid Damage, and +50% Poison Damage (but not the duration) stats were being applied to the effects of Blood Burst. Also of note, the Radius stat will not update.
This is a lie in every way. Focused Gaze has no effect on Blood Burst’s damage. I was able to easily test this on training dummies because despite the lack of text update on Radius, Focused Gaze does affect Blood Burst’s radius, leaving it at nearly double the base effect’s radius.