Thanks for the posting your Query on HCM,
In your cash the boils
are gone but there is a white patch
. so there will be nothing to apply as so early just wait and watch the condition till next 10 or 15 days . most probably white patches will be removed itself. Becouse in Iching or any skin disorders dead cells take some time to be out.so don't worry abut this.If there will be no recovery then after 10 or 15 days consult you dermatologist
for the same.