After giving him the medicine, there are stairs behind you to climb up. After climbing up, go right. Don't enter the heavily fogged gate on the right yet; go ahead to collect the materials first before entering.
After obtaining the materials, enter the gate to trigger a cutscene. After watching the cutscene, there will be a save point and a Memory Blossom in front of you.
This Memory Blossom is "Quan Chi" Memory Blossom #1.
