swelling is not cancerous. Now you need to undergo certain blood tests to ascertain the type of thyroid disease you are suffering from. This is to be done after atleast 12 hours fasting and at an NABL certified lab(avoid Thyrocare - very unethical company!)
the tests are: Haemogram,
TSH, FT3, FT4, antiTPO levels, ATG,
Lipid Profile. when reports are ready, use the Practo app on your smartphone to me under ENT Doctors in Bangalore and consult me via Direct Teleconsultation (pay Practo ₹400 towards my consultation fee). then upload all the reports and I will call you through Practo's VoIP servers and advise you appropriately.