This study aims to compare three treatment approaches for the erosive form of oral lichen planus, a chronic inflammatory condition that often causes pain, impaired oral function, and frequent relapses. Sixty adults with a confirmed diagnosis will be randomly assigned to photobiomodulation, Photodynamic Therapy, or topical clobetasol, which serves as the current standard of care. The project investigates how effectively each method promotes healing of erosive lesions, reduces pain, improves oral functions such as chewing and swallowing, and prevents recurrence after treatment. Before enrollment, participants will undergo microbiological testing, tissue autofluorescence assessment, and histopathological confirmation. Treatment will follow strict protocols tailored to each therapy type, with PBM applied twice weekly, PDT administered once weekly for six consecutive weeks using toluidine blue as a photosensitizer activated by a 635 nm diode laser, and clobetasol used twice daily for thirty days. Clinical outcomes will be measured using lesion size, standardized scoring systems, and patient-reported scales for pain and swelling. Follow up at one week, one month, and three months will document healing progress and relapse rates. Safety monitoring includes evaluation for infections and adverse reactions. The expected outcome is to determine which therapy provides the most effective, safe, and durable improvement. The study may offer evidence supporting laser based methods as alternatives that avoid the risks associated with long term steroid use.