Use soap and warm water, lathering your hand for 20 seconds before rinsing. Use regular unscented soap to wash your hands. This will prevent any chemical irritants from exacerbating the blister site and prevent transmission of any bacteria from your hands to the fragile skin area once the blister is popped. Antiseptics such as betadine are available at most pharmacies. However be careful with betadine as it can temporarily stain the skin and can stain clothing and other surfaces. Gently pour the betadine or rubbing alcohol over the blister and surrounding area. If you are washing the site with soap and water, use a regular unscented soap, lather your hands, gently wash the affected area but be careful to not apply pressure so you do not pop the blister, and rinse well. It is best to use a single use, pre-packaged, sterile needle or scalpel blade, often found in pharmacies and medical supply stores.  If you choose to use a sewing needle from home, soak it in rubbing alcohol first. Do not insert the needle or blade into a flame, which gives off carbon particles that would irritate the skin and possibly increase infection.

How would you rephrase that briefly using Vietnamese?
Rửa tay. Rửa vết phồng rộp bằng xà phòng và nước, bôi cồn hoặc thuốc sát trùng. Chuẩn bị kim và lưỡi dao.