Can understand your concern..
As per your complain sore throat
along with reddish and bruised appearance of throat are signs of throat infection
As you had tonsils removed in the childhood the throat becomes more susceptible to infections as the tonsils act as the barriers for the infection and prevent it to proceed from mouth to other parts of body..
Thrush is also an outcome of absence of protective barrier as it is an opportunistic infection
. In case if you can also see white cheesy patches in he throat then the infection can be a relapsed fungal infection
In case if it is only sore throat and redness it can be bacterial or viral infection..
You should consult an ENT expert and get evaluated for the exact cause of the problem..
In case of thrush antifungal treatment has to be taken like oral fluconazole
and nystatin mouth washes and adding probiotics like Yoghurts and garlic in diet..
In case of bacterial infection antibiotics like amoxicillin
etc can be taken..
In case of viral infection antivirals are not needed and for both bacterial and viral infection a few other treatments like salt water rinses,throat lozenges, avoiding spicy food, drinking plenty of water and taking Ibuprofen to relieve pain and infection can help..
Hope this information helps..
Thanks and regards..
Dr.Honey Nandwani Arora..