There are many treatment options available for decreasing pigmentation.
The treatment plan that you have outlined seems appropriate and the concentration of glycolic acid is also basic - for home/self application.
There are other options available to you. You may read more about them at: http://www.skincarebeautyzone.com/skin-disorders/different-ways-to-treat-hyperpigmentation/
You should have patience and trust your doctor for some time and then make a decision as to the need to change or revision of therapy.
Hope this helped. Let me know if you may need any more information.
omg iv had the xact same problem since march and now its august of 2009. My dermatologsit said basically wut i had was an allergic reaction contact dermatitis which caused post-inflammatory hyperpigmentation. Basically wut it looks like, my lips are darker brownish in color, it looks like dirt on my lips which used to be really pink and are now splotty brownish in color. My dermatologist said that there is nothing i can do at all. she sid to wait it out...but i was thinking, there MUST be something that can be done about this, its totally emabarassing and even with lipstick or something else on my lips u can tell that its discolored....the kojic , do you think that would work? have u tried it yet? please let me know if this works, also if it irritats ur lips at all? b.c i dont want it to irriate my lips and infame them etc... PLEASE ADVISE IF YOU CAN!!!!!!!!!