Enlarged pores are not simply a sign of "oily skin". They come from several things at once: oil production, a loss of elasticity in the tissue around the pore, and a build-up of dead cells and impurities which fill it and make it look larger and more visible, particularly across the T-zone.
What actually widens pores
Excess oil is only part of the story. Sun exposure accumulated over the years, age, which reduces the elasticity of the tissue, and cleansing that does not suit the skin all make pores more noticeable.
This is why the same face can have clearly visible pores on the nose and forehead and almost imperceptible ones on the cheeks: skin is never uniform, and has to be read area by area.
The most common myths
Pores do not "open" and "close" like doors: cold water does not permanently shrink them, just as steam does not really widen them. They are fixed structures, and what changes is how visible they are, depending on what they hold and how much elastic tissue surrounds them.
Washing your face more often does not solve it either. On the contrary, cleansing that is too harsh or too frequent can irritate the skin and increase oil production in compensation.
What actually helps
The most effective route is to understand what is happening in your skin right now, whether excess oil dominates, or a build-up of impurities, or both, and to choose a treatment accordingly, rather than trusting the next miracle product.
