Re-entry into US from another country for Chinese citizen

[hanitakashi]

Hi I am traveling to Boston US in September to visit my friends and after two months, we plan to take a trip to Portugal (either Porto or Azores).

After I will come back to Boston, what will happen to my tourist entry in USA? Will it get extended by 2 months since I left USA and came back? Or will my last day in USA stay the same https://xender.vip/?

I have tourist visa to USA that allows me to stay in US for 6 months.