Have you tried pantethine? I don't recommend megadosing that one in the multigram per day range.
500 MG daily to see if there is any reaction and wait at least 2 weeks before trying some other dose or something else if nothing improves.
Wash skin two times only daily with a gentle cleanser.
Watch what you eat too. High carbs/sugars will create more sebum. Avoid dairy for two weeks at least and check skin condition. Avoid high sugal/carbs for two weeks and check results. Avoid both and check for two weeks. Try in any order.