A home remedy you could safely try is to hold a hot, damp compress against it for 15 minutes (continue to keep the cloth hot by refreshing it in hot water), and then see if the cyst has opened and drained.
If you can't refrain from squeezing it or working on it with your fingernails in some other way, do see a dermatologist, since fingernails and pushing the pus down into the pore are ways to give yourself an infection.
Start with good skincare if you want to get rid of the pimples on your forehead.
Use a mild cleanser to wash your face twice daily. Your skin's extra oil will be removed by doing this. Try an over-the-counter acne cream with chemicals like salicylic acid or benzoyl peroxide if that doesn't help.