Will Singulair (medicine for asthma) help to heal swollen breast after lift and augmentation?

Singulair is used as a FDA off label usage to treat Capsular Contracture and in some cases of recurrence of capsular contracture in a preventative fashion. This does not apply to you for the following reason: Although capsular contractures following breast augmentation can occur just about anytime, most women start having symptoms around three months after their breast implant surgery. This is because it takes some time for a capsule to form and then to scar down (contracture). Therefore it is probably too early at 3 weeks to be concerned about this problem. Your signs and symptoms are most likely from muscle spasm although other factors could also cause this. Your plastic surgeon should be able to sort this our in short order.

I think the course your have been given is a good one in general.  I wouldn't recommend operating this early and the singulair could possibly help (I also use this from time to time).  If the breast is still painful and firm at 6 months you may need a capsulectomy to remove the scar tissue that you formed around the implant.

The science behind it makes sense but in our field we typically dont have great studies to justify a lot of things we do, make sure to have your liver function checked!