Pigment Gets Darker After 2nd IPL Treatment

I'm nearly 50yrs old lady,n i'm Malaysian and my skin is fair with pigment.I did IPL pigmentation 7th April for the first treatment and my skin goes red and my pigment turns dark immediately after treatment. But my pigment had become lighter after the 4th days than before.

So,i decide to go back for the 2nd treatment the next 20th April again to clear all my pigment. But after i did the 2nd treatment,my pigment doesnt change any lighter but go darker than before.why will this thing happen?

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