In short, nothing.
Microblading doesn’t actually do anything to your natural eyebrows and the impressive effect that we see in people who have had microblading treatments is the treatment working alongside what was there before.
The treatment you receive is actually being performed on the skin underneath and around your natural eyebrows rather than on the hair that makes up your brows. In short, small hairlike incisions are made to the layer of the skin known as the dermis, and at the same time, a pigment is worked into those incisions. Microblading is known as a ‘semi-permanent’ procedure as it is distinct from the permanent procedures used by tattoo artists who inject ink below the dermis layer of your skin.
This is why those who perform microblading are trained to understand the interaction of the hair and the semi-permanent pigmentation so create shapes and effects that give you the look and style that you desire.
It’s sometimes asked why microblading couldn’t be performed as a permanent procedure and it largely comes down to being able to change your style as time progresses if we ignore the medical aspect of the question. We have written another post about this in more detail which you can find here.