4 weeks into Accutane and I have developed a "never ending" pimple on my cupid's bow, why won't it go away?

i am about 4 weeks into acutane with 40mg once a day. i seem to have developed a "never ending" pimple on my cupid's bow. it has been there for about 3 weeks and for a couple of days it would not pop but is now a white head and will pop with ease

No doctor answers yet