I'm wondering if this pimple i have on my forhead turned into a boil or mesa or is just infected. it has light brown or yellowish brown pus that came ?

It's possible: Pimples usually start out with a simple opportunist germ that invades the trapped pores. If/when the pimple opens to the surface other germs can also be involved & if a boil forms it is often staph.The MRSA strain varies in prevalence but in my area is found in 60-70 % of boils I drain in the office. A visit to the doc or dermatologist can decide If yours needs to be treated with abx or drained.