Is there anything else I should check or should be worried about?
You can check your fan circuitry (up to the thermal switch) by grounding the lead to the thermal switch. The fan should activate when the lead contacts electrically frame ground.
If the fan does not turn under this test condition, the fan relay or the fan motor itself could be malfunctioning. You can test the motor in isolation by applying + 12 VDC to the fan's blue wire.
The thermal switch, at the bottom of the radiator, grounds the lead at a temperature around 200 degrees F. to activate the fan relay and the fan. You can boil it on the stove if necessary to test.
This link takes you the BigCee's fan circuit wiring diagram for the KLR650 (Generation 1); same as the KLR250's except: No fan fuse on the 250, IIRC:
Back to the question at the top of this post: If you drain and refill your radiator in your "treatment," be sure to burp the radiator fully; the KLR250 is very sensitive to air pockets in the coolant plumbing.