Hello, Thanks for the query to H.C.M.C.
625 mg is a normal dose of this drug and you are using it for tonsilltis.
Your's query is that due to this drug the size of penis has reduces and it became thinner somewhat at the time of erection.
Note in mind that no drug is able to decrease or increase the size of penis at any cost ( oral).
There is a misconception in young that size of penis matters but that is not a fact rather its performance during sex matters.
So remove any wrongs from your brain and live happy life.
Good luck .