@floricik It's great to hear that your hen seems to be improving and showing some appetite! If one of her wattles is swollen and feels hot to the touch, it's possible that she may have indeed been bit or stung by something. Insect bites or stings can cause localized swelling and discomfort.
To...
I'm not a veterinarian, but based on the symptoms you described, it's possible that your hen may be suffering from a respiratory infection or some other illness. The slimy inside her beak could indicate respiratory mucus. It's good that you separated her from the flock to prevent potential...