Thank you for the additional information.
Allergies certainly can cause irritation of the tonsils, but when pus is developing, there would be more of a concern that the tonsils are becoming infected. There would be a greater concern if there were redness and swelling, but any pus has some level of concern. If the problem is only local irritation with no evidence of infection, allergy would be one of the most common causes.
There is another common possibility that could cause whiteness on the tonsils, a condition called tonsil stones or tonsilloliths. This is the accumulation of hard white material in the infolding of the tonsils and are generally not a concern. It would require a proper examination to assess for this problem, but without other associated symptoms, this problem is more of a possibility.
From the perspective of the lymph nodes, it is a good sign that the lymph node is smaller, and is a general sign that it is healing. It may take quite some time for it to completely resolve, as the other expert noted above, but as long as the size is getting progressively smaller, that is always a good sign.
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