Nano brows, also known as nanoblading, is a semi-permanent makeup technique that involves using a digital machine to create hair-like strokes on the brows. The process is similar to microblading, but the needle used in nanoblading is much finer, which allows for more precise and natural-looking results.

As for the pain, it's important to note that everyone has a different pain threshold. However, in general, the procedure is often described as mildly uncomfortable rather than painful. The sensation is often likened to a scratching or a tickling feeling.

Before the procedure begins, a topical numbing cream is applied to the brow area to minimize discomfort. This is usually left on for about 20 to 30 minutes to take effect. During the procedure, you might feel a slight scratching sensation, but it should not be overly painful.

After the procedure, there may be some redness and minor swelling, but this usually subsides within a few hours. It's also normal to experience some itching and flaking as the brows heal.

Here's what you can typically expect during a nano brows procedure:

1. Consultation: The practitioner will discuss your desired brow shape and color. They may also draw on your brows to give you an idea of the final result.

2. Numbing: A topical anesthetic is applied to your brow area to minimize discomfort.

3. Brow Shaping: The practitioner will then use a digital machine with a nano needle to create hair-like strokes on your brows.

4. Pigment Application: After the strokes have been created, a pigment that matches your natural brow color is applied.

5. Clean Up: The practitioner will clean up any excess pigment and apply a soothing gel to help with healing.

6. Aftercare Instructions: You'll be given instructions on how to care for your new brows to ensure they heal properly and last as long as possible.

Remember, it's important to follow all aftercare instructions and to avoid picking at your brows as they heal to prevent infection and ensure the best possible results.