The white mark on your tonsil
can just be debris of mucosa as it collects in the folds of the tonsil.
However as it you recently had an infection it may also be because of the infection leaving some pus filled spot.
As you have already seen an ENT specialist
and he may have prescribed you antibiotics there is nothing to worry. Just make sure you have taken the entire course of antibiotics prescribed.
Also take some warm water to drink and gargle it will reduce your symptoms.
If you still feel uncomfortable with the spot you should see the ENT specialist and get it checked.