When you get back to Charity after resolving the main quest Find Faith, the information you were promised will have to wait for a bit longer. Talk with Charity again and offer to do some work while you wait. This will start this side quest, which revolves around completing two other side quests that will also add to your log; The Bad Payer & The Exhibitionist.
Once both those side quests are complete, return to Charity. For the Bad Payer, be sure to give Charity all the Serum back, “Squeezed him till the last drop” - 50 Serum, be sure to not spend it before turning in this side quest - and not keep it as this will again unlock a further side quest.