We are Indian nationality. Is it possible to get VOA at Lo Wu or Guangzhou for my son to join with us this weekend.

I am holding HK working Visa and staying in Hong Kong. I am having Valid Chinese business Visa as well. We have planned to visit Guangzhou tomorrow. My son of age 13 years, holding Chinese visit L is expired and could not able to get new one within this time.
Pls guide us.