Thank you for your question. Differin and Epiduo are the two retinoids available over the counter. Both used to be prescription only. Epiduo also has benzoyl peroxide in it which makes it suitable for pustular and nodular acne.
I would go with Differin if the intent is to prevent milia. However, do take note that Differin will not treat milia. Electrocautery or CO2 laser ablation are still needed for that and a regime of treatment and maintenance should be worked out by your doctor for best results.
Hope this helps and all the best.