I had IPL laser for broken capillaries and 2 of the capillaries on my forehead are now black. How long until they are gone?

Hi IkkracinskiThis is a positive sign that the broken capillaries have absorbed the energy emitted by the IPL. Give it up to a month for your body to metabolize and absorb the vessel. Most likely it will fade away within one month of the treatment. Occasionally you may need another treatment even with this positive response. 

You likely got a good response to those vessels and need to give it a few weeks to clear.  Best, Dr. Emer.

Intense Pulsed Light (IPL) is very effective for treating superficial dilated capillaries. The process works by the absorption of the light energy by the blood in the capillary. The light energy is converted to heat energy as the light is absorbed by the red color. The heating of the blood, subsequently heats the vessel, which damages (or destroys) it. Immediately following treatment, some vessels remain red in color and others are darkened (grayish). Those that are darkened are effectively treated, and unlikely to require additional treatments. Those that do not change color may lighten or disappear over several weeks, or may require additional treatments. IPL treatment settings are usually designed to minimize downtime; to injure the desired target without injuring the adjacent skin. IPL treatments are, in a way, a form of progressive injury; injure the vessel again and again until it can't repair itself.Back to your question ... When capillaries immediately turn dark (reddish-grayish-black) in color, they are usually effectively treated. The dark color will not remain.This coloration usually fades in several days, but may take up to a week or a bit longer to resolve.Best wishes.