Does /targetlasttarget not work here?

[TheFishyOne 9]

As a Tankadin, I'm trying to create a macro that targets myself, casts Lay on Hands, then targets whatever I had targeted last. /targetlasttarget doesn't seem to work here. Anyone have a workaround?

[meridaw 11]

/run TargetLastTarget()

[meridaw 11]

/run TargetLastEnemy()

[meridaw 11]

/run if not buffed("Lay on Hands") then CastSpellByName("Lay on Hands") end