credit score drop from $5 on card

a few months ago my credit score dropped 100 points (from 750+ to 650+) because there was a $5 charge left on my Bilt card. (I never use that card but I must have for something and forgot.) The card has since closed since I didn't opt into the new Bilt card. Is there a way to get my credit score back up? (It has since increased to 690 but obviously I'd prefer if it was 750+ again.) who would I call, Bilt/Wells Fargo or a credit company?