Intense pulsed light is a popular hair removal treatment that is usually safe when used by an experienced practitioner.
However, there are documented risks for IPL including hypopigmentation (white spots) and hyperpigmentation (dark spots).
Your white spots might be a case of Hypopigmentation. My suggestion for the treatment of your possible hypopigmentation:
1. Avoid the possible trigger - IPL
2. Consult a qualified doctor for a formal diagnosis
3. Topical creams to stimulate pigmentation recovery
Hypopigmentation is a challenging condition to treat. Please seek advice from an expert doctor.