Severe acne on jawline, cheeks and chin.

I have oily and generally acne prone skin and used to get the occasional 2-3 acne during my periods which used to subside within 3-4 days by itself. However, for the last 2 and a half months I have been suffering from severe acne breakout that started on my chin and jawline which then spread to the cheeks as well as on the neck area around the ears. I haven't taken any medication for it but the same are just not subsiding. They are painful and pus filled. There has been no dietary or lifestyle changes nor have I started using any different or new products on my skin. I got my hormonal tests done as well a year back which came back normal. Kindly guide me as to what could be the reason behind this sudden stubborn breakout.