More Effective Melasma Treatments?

I developed Melasma above my lip during my first pregnancy. It worsened during my second pregnancy. It has now been 14 months since that pregnancy, and I have seen my dermatologist.

I have started using Lustra cream, and have had one IPL treatment, and two TCA Chemical peels. I understand the Lustra can take months to show results. However, the IPL and Chemical peels don't seem to have much effect on the melasma. In fact, sometimes I think it may look worse than before. Are there other procedures or treatments I should try instead that may be more effective?