After the pulp opening treatment, there is a place where I dare not bite. A few days later, my gums began to swell and ache. What is the reason? Could it be that the pulp was not washed clean?

Pulp opening treatment does not remove the pulp, but only carries out anti-inflammatory and sterilization treatment. You're afraid of biting. You should have psychological fear. Most of the treated teeth can be used normally. Gingival swelling and pain is the pain caused by pus in pulp cavity stimulating and compressing nerves. I suggest you check your teeth again to see if there is any inflammation.