Please tell me how to prevent the spread of small pimples on my forehead.

Milia suddenly spread on my forehead, looking like millet grains scattered.
I am curious about exactly what I should be careful about when washing my face or applying cosmetics.

What is the cause??

I would like to know if the cause is stray hairs touching my forehead or shampoo or conditioner foam getting on my forehead when washing my hair.

Please let me know if I should completely avoid using exfoliants like scrubs or peeling gels that I usually use for the time being, given that my skin is breaking out.

Should I change the basic skincare products I usually use, or is it okay to continue using them?

Or I am wondering if I should switch to a product that is low in oil and does not clog pores.

It would be a great help if you could specifically tell me what I should be careful about in my daily life to prevent the forehead blemishes from spreading further.