There could be different reasons, like hormonal imbalance or dandruff or skim care routine or combination of all. I would suggest consultation with experienced Doctor would help , still I would suggest few products and medicine for home care
Next Steps
You can start with anti dandruff shampoo like sebamed anti dandruff shampoo twice a week if you have dandruff
You can apply clindamycin clear gel on acne for 8 days but it’s not a permanent solution
Health Tips
Get a consultation with a cosmetologist