Got second degree scald burns on my hands 4 days ago. they are sensitive to the touch, red on the edges with a light yellow scab color on them. no drainage of any kind. are they infected?

I believe you're describing inflammation rather than infection at this time. Do not break any blisters. Wash gently with clean warm water, pat dry & apply an antibacterial ointment. Cover lightly with a sterile nonstick pad. Observe for spreading redness,pus drainage,swelling or increased pain which would be worrisome signs of infection requiring a physician's attention.

Agree with Dr. Colontino. If there are any raw areas, apply triple antibiotic cream. If redness spreads or red streaks appear see a doctor.