I don't think the cold medicine exists. As for other NPCs, the developer included a memo among the game files that hints their location. I don't know which is which.
◆For those who still cannot proceed◆
- A woman who appears near public baths from Wednesday to Thursday seems to be saying something meaningful!
- Now that I think about it, there seems to be a TV in the main character's room...?
◆For those who do not understand the meaning of fortune telling◆
- On Tuesday in the library (upper right building) behind the sign-like object on the right...?
- In the shadow of the tree under the convenience store parking lot on Thursday...?
- When I investigated the detached wall at the bottom right of the public bath on Friday...?