Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concern... As per your complain all the symptoms that you have indicated of having a pink eye along with fever, cold, sores in mouth and swollen gums are all due to Viral infection leading to Viral Conjunctivitis and Viral Gingivostomatitis.. Due to infection, the immunity of the body goes low and also in such an early age the immune system is not completely developed, therefore, it is leading to fungal infection on the tongue causing Oral Thrush and it is the cause for white coating over tongue.. You should consult a Paediatrician and get him evaluated.. In case if the Viral Infection is diagnosed you should give him Tylenol or Motrin for pain relief.. Do cool compresses over gums for relief from Inflammation and reduction in swelling.. In case of pain in the sores on tongue a numbing gel like Oragel can be applied.. In severe cases antiviral Oral and topical Medication like Acyclovir therapy is given to the patient to reduce the duration of illness... Give him cool and bland diet.. Give him sufficient rest.. Maintain a good Oral hygiene and brush his teeth twice a day using an ultra soft toothbrush.. For thrush Candid mouth paint will help in resolving the infection.. Hope this information helps.. Thanks and regards.. Dr.Honey Nandwani Arora..