Should I stop Cosmelan 2?

I had my Cosmelan I mask about a week ago and started applying Cosmelan II 48h after, as recommended. By day 7 the pain is unbearable, it seems like the product was applied even on my eyelids as they are extremely tight, itchy and hard to keep my eyes open. Applying Cosmelan II is simply too painful. My question is: what happens if I stop using C2? Will my skin go back to normal? Will I lose the progress of Cosmelan I?