How can I treat an enlarged/clogged pore that is very stubborn? Punch Excision? Dermapen? Other?

Enlarged pores can be treated by several methods the simplest and most cost effective is by using microdermabrasion. Microderms will extract black and white heads from the base, clearing out the pores. Large pores can also be minimized with dermapen microneedling, fine holes are created stimulating collage productions to minimize the pores. Photofacials can help with redness and improve the tone of the skin but will not minimize the size of the pores. Large pores are a result of excessive production of oil and debris congesting the pores. In order to minimize pore size oil must be controlled using a chemical peels, microderms, good skin care products such as Skin Medica Retinol, AHA/BHA cleanser, etc. 

I choose a particular laser based upon the size of the pore, skin type of the patient, and expectations. I find that the most reliable method is with INFINI RF, micro needling using energy. This beats all my Fraxel lasers and chemical peel techniques. Very little downtime, and it is ideal for small to medium size pores. Fraxel 1927 comes in a close second in the high density setting. 
Chemical peels such as TCA (70-100%) placed focally in the pores is an excellent treatment for large pores. Fully ablative laser are excellent, but the downtime is long. I use both erbium and CO2. Fractional CO2 medium density can work, but you require 3-6 sessions. More in the pore section in the web reference below. 

Pore size reduction treatments should be tailored according to the patient IMO.

Regards

Dr Davin Lim

Laser and aesthetic dermatologist

Brisbane, Australia.