Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns..
As per your complain ulcers on tongue and throat along with fever
and runny nose seems to be most probably due to Viral Infection..
I would suggest you to consult an Oral Physician and get evaluated and a thorough clinical evaluation and investigations like blood tests and oral swab culture can help in diagnosis and treatment can be done accordingly..
In case of viral infection antiviral medication
As of now you can take supportive treatment to relieve pain like gargle with numbing mouthwash containing Lignocaine..
Do warm saline gargles..
You can take anti inflammatory painkiller like Ibuprofen
Avoid spicy and hard foods..
Take a soft and bland diet..
You can also suck ice and do cool water rinses..
A painkiller injection like Voveran
can help in reducing pain and inflammation..
Hope this helps..