Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns..
As per your complain sores or blisters inside the nose can be due to infection caused by bacteria or viruses and in case if it is preceded by cold and cough, it seems to be most probably due to
herpes simplex virus causing cold sores..
It can also be due to bacterial infection causing Impetigo and it is also a commonly seen cause for blisters inside nostrils..
It is caused by
Staphylococcus bacteria..
I would suggest you to consult an Otolryngologist and get evaluated and a thorough clinical evaluation and investigations like Nasal swab culture, blood tests, nasal
endoscopy etc can help in diagnosis and treatment can be done accordingly..
In case of viral infection anti-viral medications like
Acyclovir, Valacyclovir etc can be advised..
In case of bacterial infection antibiotics can relieve..
Do cool compresses over the nose..
Take anti-inflammatory painkiller like
Ibuprofen to reduce pain and inflammation..
You can also do saline nasal irrigations..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.