Hi Thuhuyen. I'm sorry you are having some problems with your laser treatments. My 16 year-old grandson has facial pws. I can tell you what works for him. The best tip is to keep your skin from becoming dried out. Apply an ointment, like bacitracin or polysporin, very liberally on the treated area. Re-apply the ointment during the day, as needed. You might ask your doctor what ointment they would recommend. Also, for the swelling, use an ice pack. Stay out of the sun.
If you don't mind my asking, how experienced is the doctor doing the laser treatments? Also, how many treatments have you had, and at what age did you begin laser treatments?
Please let me know if you have any other questions, or if there is anything else I can do to help.