Since you have diabetes and take Glycomet, managing skin infections promptly is very important as high blood sugar can delay healing. For temporary relief from itching, a generic antihistamine like cetirizine is generally safe to take. Warm compresses can help soothe the boils on your head, but please do not squeeze them. Because diabetes makes you more prone to spreading infections, it is highly recommended to see a doctor or dermatologist. They can safely evaluate if you need prescription antibiotics and ensure your blood sugar levels are well-managed to help your skin heal quickly.