To me, the main impact of this war was that it acted as a wedge to open China up. As China was forced to open up more and more to the West (and eventually Japan) it lost its sovereignty and its whole society was undermined.
The actual immediate impacts of the war were not that great. Some opium came into China. Some ports were opened up and some missionaries were allowed in. But in the long run, this was just the start. From there, the British and other countries started to demand more and more access until they practically destroyed the soveriegn power of the Chinese government.
