I Went To Dentist Because My Tooth Was In Pain

I went to dentist because my tooth was in pain and he took X Ray and it showed nothing. told me I had a sinus infection and gve me zithromax and I had a reaction so I stopped taking it. I went to a eat,nose throat doctor and he said I have cankersores on my gums to rinse with water and salt and it will go away. I feel alittle better today. I am worring hoping they are right. Could you help me with this situation. Thanks
Holly