Normal To Have a Grid-like Dark Brown Lines Across my Forehead After IPL? How Long Will This Last?

I had my first IPl treatment yesterday for multiple hyperpigmented sunspots on my face. I did my research and selected an experienced dermatologist office. The results were as expected right after the procedure (mild pain during procedure, burning sensation for a few hours, and then darkening of the hyperpigmented areas with the coffee grind look). However- I also have a dark brown grid-like appearance on my forehead? Will this resolve? When and how can I speed this along?