My neck is red after retinol. Should I use more moisturizer and continue?

I would pause the product causing the irritation rather than push through. The neck often tolerates retinoids differently from the face, so the same amount and frequency should not be assumed to fit both areas.

Do not push through retinol irritation on the neck

Check how much and how often you were applying it. Persistent pain, marked redness, or a rash should be assessed. If it is a prescribed treatment, contact the prescriber about how to proceed.