Digestive problems, maybe. You could try changing your diet. I always like to recommend the paleo diet.

When I have those acne on my forehead it means I'm having a reaction to something I put on my face or infection in the body. Takes 2-3 weeks to clear up once I identify and stop using what my body doesn't like. Takes one week for these acne to develop when I start something new that my body doesn't like.

Last time I had food poisoning. Came up a day later. Lucky I was on antibiotics and it went away by the time my medication finished.

Have you been using something new lately??

The colourless bumps are closed comedones/whiteheads (some people call pustules whiteheads because they have a yellowish/white head)

Anyway, i find that exfoliating helps them. I used to use a scrub, with bits in but i found this to be quite harsh, so now i use a chemical exfoliant, Glycolic acid(its derived from the sugar cane and has many benefits). I got mine in a facewash form, dont go for the peels yet.

These arent painful 'pimples' or anything but in some lightings they can look weird. I dont pick them unless its already pushing itself out.

People say steaming helps open the pore, so have a look into that.

Good luck bub

Forehead pimples are the most stubborn. Try benzoyl peroxide on your forehead see what happens.