NAC Topical For Glowing Skin?

Hi. Im curious if anyone has thoughts/ warnings about applying pure NAC powder dissolved in water, on skin. It stinks.

I have been applying it to my face and hands at dosage of half a gram in 3 or 4 shot glasses of water ( I don't measure the water). I don't do it every day. Ive not noticed any bad experience from it. I noticed nothing at all, good or bad, other than the smell is horrible. I was hoping it would fade freckles and sun damage, and make my skin glow.

Does anyone know if it is photo toxic? Would it be better to apply it at night?

Is applying it topically a bad idea?