Should I Be Worried After My Autistic, Non-verbal Toddler Drank A Small Amount Of Phenyl 4 Hours Ago?

Hi my 5 year old son drank phenyl in small amount he dint do vomiting nor motion he is fine its almost 4 hours and he autistic and non verbal i dont know what to do i went to pediatrician he said he is fine but i dont know what to do i am seriously worried what to do??