After IPL how long does hyperpigmentation last?

It depends on what type of pigmentation was treated and the type of treatment performed.  For standard superficial (epithelial) pigmentation (sun spots, freckles, etc) the peppering after IPL will usually take one to two weeks to lighten. 
In other cases of pigmentation, usually pigment that is deeper in the skin, IPL may not be very effective at eliminating or lightening this pigment and therefore you won't see a dramatic improvement.  This can be especially true of melasma. I have many colleagues who can treat certain kinds of melasma with some success using IPL, but I prefer other laser modalities, microneedling, and chemical peels in addition to a skin regimen.
If you don't see any improvement in 1-2 weeks then it is likely that the pigmentation you have is deeper in the skin and therefore not as effectively treated with IPL.

Our office has many different treatments for scars depending on the depth of atrophy or hypertrophy. Scars require a combination approach using our HI DEF protocol which uses a combination of lasers, topical scar modulation, and RF treatments to pixelate scars, improve contour, reduce hyperpigmentation, and improve the visibility of the scars so that they are no longer visible in ambient light. Everyone has a unique pattern of scarring and we employ our HIDEF technique to improve texture, color, contour, and topography. We often use a combination of treatments that begin with a careful examination to examine the micro texturing of the acne scars. Atrophic scars and indented scars can benefit from injectable fillers such as Radiesse, Sculptra, and Restylane with or without subcision to remove tethered scars and atrophic depression. Hyper-redness in scars can be improved with V beam laser, Excel V, BBL, IPL, and Venus RF to improve the redness and reduce the visibility of deep scars. Fractional Thulium laser and clear & brilliant can also reduce the inflammation and redness of the scar when combined with topical therapy. Fractional lasers such as Fraxel, erbium, and CO2 laser can be combined with radio frequency and also fractional RF to improve textual issues and microtopography. Subcision and TCA cross are also used for deep ice pick scars and narrow valley scars in order to improve the micro texture. Above all, our combination approach with our clinical nurses and board-certified plastic surgeons can improve the quality of your skin by using at home Melarase creams combined with PRP treatments in our office to improve your skin quality and tone. I recommend getting a formal evaluation with an experienced team of experts in order to reduce your scarring.

Finally, hyperpigmentation of scars can be improved with at-home Melarase AM, Melarase PM, and Melapads to help reduce active PIH and melanin deposition.

Best,
Dr. Karamanoukian
Realself100 Surgeon

thank you for your question.  IPL treatment treats red vessels, hyperpigmentation and it improves the texture of your skin by producing collagen and elastin. you will pepper after the treatment and the dark spots will appear darker before they flake off. do not be alarmed.  This takes 2-4 days depending on your skin type and the intensity of the treatment.Always consult with a physician to make sure you are a good candidate.