If scoliosis is not that serious, what is the treatment needed to be back from normal?

Therapy helps. For patients with mild scoliosis, physical therapy or chiropractic care can be very beneficial by improving core strength.
Rehab exercise . Most of the time scoliosis is not a serious issue. However, the curve must be measured as a baseline & followed to make sure it's not progressing. A pt program designed w/ emphasis on core, trunk stability & pilates is the ideal way to get back to normal.
Yoga & Surfing. Mild scoliosis in 20's male compensated by back muscles toned by yoga & swimming. Surfers have exceedingly strong & well functioning backs. Avoid extreme sports, ephemeral glory, painful chronic musculoskeletal injuries; caused by mechanical falls vs. Firm immovable objects &/or surfaces. Often scoliosis is functional & dissipates when prone; as gravity absented above an injured unstable pelvis.