Doctors can use technology to evaluate preexisting health conditions so one does not push themselves too far. Technology can help monitor your heart rate, blood pressure, fat percentage, etc. This can give a base to know what to know where/ how much you improved when you look back. Technology can also be your own equipment like a treadmill which makes you more fit.
If the boil ruptures under the skin, inflammation and infection spread quickly and new lumps form nearby. HS is a progressive disease so it is bound to get worse over time. It can be unpredictable. It is different for every person so it can be hard to predict.
