If you are finding the pigment dries fast, you can place a piece of saran wrap over the eyebrows when you are masking, as this will help keep the pigments moist and easy to wipe off. Ensure you're wiping your blade or machine throughout your procedure to make sure the pigment is not drying on the tool.
If you are finding the pigment dries fast during the procedure, please take a wet cotton pad soaked in diluted green soap and place it over the eyebrow for a few seconds. This will make the pigment wet again. After a few seconds, just give the cotton pad a wiggle wipe and the pigment will come off! Here is a great video for reference.
Tina's go-to recipe she uses in her soap mix:
Use 1 part Dr. Bronner's Baby Unscented Castile Soap to 9 parts water. Your mixture should be 10% soap to 90% distilled water. Put it in a squeeze/wash bottle and squeeze onto soft cotton pads to wipe. Do not use too much soap in your mixture or it will be too foamy.