I burned my finger and have a dime-size blister. The skin was already damaged from a previous burn. I take Humira, (adalimumab) &worry about infection. Treatment?

Keep an eye on it. You will need to keep an eye on it . If the lesion spreads, fails to heal after 2 weeks, becomes tender and warmth, or exudes pus, call your doctor immediately. Otherwise just be sure to keep the area clean.