ขอบคุณทุกคนที่เข้ามาตอบนะคะ

พอดีส่งอีเมล์ไปถามที่สถานทูตแล้ว บอกว่าได้ค่ะ

Regarding this concern, please be advised that as you have stated that you already have a valid US Visa, you may use it to seek entry at any port of entry of the United States from any country as long as it is not damaged and is the appropriate type of visa required for your principal purpose of travel. The expiration date of your visa is the last day you may use the visa to enter the US and does not indicate how long you may stay in the US. Your stay is determined by DHS at your port of entry. As long as you comply with the DHS decision on the conditions of your stay, you should have no problem. You also may use your US Visa as long as the visa is a multiple entry visa (the alphabet M is annotated on the visa indicating that the visa is a multiple entry).