Thanks for your query,
As you said pimples
are large and are spreading,you also mentioned that her immune system is week so i suggest you not to do any manipulation as this will lead to more infection.
You should consult your pediatrician
so that he can have a look over the lesions and treat accordingly,she may need a course of antibiotics orally as well as locally.
In the meantime wash her face with some mild facewash and wipe it gently.
Regarding her other problem microcephaly
she needs to be evaluated and some
tests need to be done.
Give her plenty of fluids.
Wishing your child good health.