I have mild/moderate acne, using blue/red light therapy mask for it, its helping, but insomnia has worsened, does the light block my own melatonin?

Morning only: You shouldn't be doing that therapy at night as it may interfere with your sleep.

See a dermatologist: You are already taking melatonin. You may need to relax better at night. You will probably obtain best result for acne with antiandrogen spironolactone 100mg daily. Costs $16 for 3 months, very safe, much more effective. If satisfied after 3 months, continue as long as needed. There are simple relaxation techniques which help many people to sleep.