Hello and welcome to HCM,
A variation is periods is acceptable.
A normal menstrual cycle can be as short as 20 days and as long as 35 days.
Very often there is variation in the timing of the periods.
An initial regular cycle and become irregular and vice versa.
Observe your periods for some months.
If they are regularly irregular, there is nothing to worry, else you need to visit a gynecologist.Pimples
are a common problem at your age.
They are caused due to hormonal
imbalance but get resolved spontaneously.
In case they are severe and/ or have become infected, you need to consult a dermatologist
Cramping and vaginal pain
may be associated with menstrual.
You can take anti-spasmodics for this problem.
Thanks and take care
Dr Shailja P Wahal