Hello, I can understand your concern. When the teeth are about to erupt in oral cavity, the gums become little sore and kids tend to put things in mouth frequently to soothe the sore gums. This tendency to put every odd thing in mouth, makes kids at this age prone to stomach infections. As he is gagging, retching and had vomited, it might be the possibility of him associated with teething. In such case, I would recommend you to visit a pediatrician to see if he requires a course of antibiotics. In addition, the drooling of saliva because of excessive salivation due to eruption of new teeth in mouth. It will stop in some days as the kid will get used to new teeth in oral cavity. In addition, the sore gums and irritation due to erupting teeth can make a child cranky and he may scream a lot. This will also subside soon. If the gums seem too sore, you can apply Orajel to his gums to soothe them. I hope this information helps you. Thank you for choosing HCM. Take care. Best, Dr. Viraj Shah