If you keep vomiting after taking a slimming needle, it is an adverse reaction or side effect of the drug. Vomiting is a serious reaction, and it is recommended to seek medical help from a professional doctor immediately. Doctors can evaluate symptoms and physical condition and take appropriate measures to relieve discomfort. Before seeing a doctor, you can try to rinse your mouth with some clear water to help remove the residue in your mouth and avoid eating solid food to reduce the irritation to the gastrointestinal tract.