Summarize this article:

If your dermatologist offers laser treatments, you’ll likely need to make quick visits each week for about a month. Spot treatments with the laser are usually painless, although you may experience some burning or redness in the treated areas.  Like cryotherapy, dermabrasion, and chemical peels, laser treatments intentionally cause minor damage to the skin. As the skin repairs and regenerates, the IGH spots should be minimized or disappear completely. All of these therapeutic skin damage options seem to produce roughly the same rate of success, although there isn't much detailed research on them when it comes to treating IGH. Your doctor will probably first recommend topical creams (like steroids or retinoids), then if necessary move on to trying one therapeutic skin damage method at a time until you see the desired results. When treating IGH with cryotherapy, your dermatologist will essentially dip a small tool akin to a cotton swab into liquid nitrogen and hold it to an IGH spot for 5-10 seconds. At most, you may experience a minor and short-lived burning sensation where the treatment occurs. Cryotherapy is effective at removing IGH spots (within a month or so) in roughly 80% of all cases, which is in the same range as other therapeutic skin damage methods. If you undergo a phenol (or similar) chemical peel at your doctor’s office, you can expect your IGH spots to disappear within several weeks roughly two-thirds of the time. In some cases, though, you may experience scabbing over your IGH spots, or even (in rare cases) ulceration of these spots. You may also experience hyperpigmentation in rare cases, which means the IGH spots will go from being much lighter than your surrounding skin to noticeably darker. Intense Pulse Light treatments may help to even out your skin tone. The treatment uses pulses of bright light to improve the appearance of the skin. It can cause some stinging, so you will need an application of a topical anesthetic before your treatment. You will also need to wear dark glasses to protect your eyes.  IPL treatments take about 20 to 30 minutes per session, and you will need 3 to 6 treatments performed 1 month apart. You may experience some redness and peeling of your skin after treatment.

Summary:
Try weekly laser therapy treatments for about a month. Consider spot cryotherapy treatments with liquid nitrogen. Undergo a chemical peel with 88% phenol or a similar product. Look into Intense Pulse Light (IPL) treatments.