It has to get worse before it gets better
See, now I've always called bullshit on that. Things don't need to hit rock bottom to rebound. Imagine a person on his deathbed-- how the hell're things going to get worse for him or her in order to get better?
People recover from illness through rest, nutrition and (in this day and age) antibiotics and antivirals. Sure, a person is more than able to turn tonsillitis into some kind of infection from hell spreading all throughout the respiratory system by power-smoking an infection away (it's a long shot, sure, but possible enough to be concerned with), but why irritate infected soft tissue and prolong the illness (likely exacerbating it in the process) when you could chill out with the extra respiratory irritation and cut recovery time down to a fraction of what it would be if a person acted as if they didn't care that they weren't well.
Don't get the tone of the post twisted, though, I smoke through illness all the time and have firsthand experience with the shit. I probably still will despite allowing a common cold develop into bronchitis and then walking pneumonia two Winters ago. Using a bong whilst sick turns your bong into a bacterial fucking hotspot, man, moreso with every single use....
If you're going to ingest cannabis whilst sick, best to go with edibles. Second-best option is vaping, but even that can be harsh on certain persons throats.
Again, this is more of a do as I say and not as I do kind of thing. I know the
best option... but unless it's physically painful to smoke, I'm probably smoking.