So my initial thought was to unscrew the fan and clear out the dust that way. Halfway through the process of unscrewing the fan (and heatsink I think? again I apologize) I decided I shouldn't do that as I really don't know enough about what I'm doing in case something went wrong.
You may have dislodged the thermal paste between the CPU and heatsink. Not totally, but enough to make a difference.
The only way to fix is to take it off and reapply.