Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Toes that become cold, pale, blue, or difficult to move require immediate assessment.
Report a loose, damaged, wet, or painful cast or device promptly.
Contact the treating team urgently if a cast or boot causes new rubbing, drainage, marked swelling, worsening pain, or numbness.
A new warm or swollen foot should not wait for a routine appointment.
Seek prompt assessment and reduce weight-bearing until a clinician advises otherwise.
During active treatment, follow-up is usually frequent.
The team may examine the skin, check swelling and warmth, assess the cast or boot, and repeat imaging when needed.
Routine care may involve a diabetes clinician, podiatrist, foot and ankle specialist, orthotist, wound team, or physical therapist.
The article also says
After the active phase, lifelong foot surveillance is important.
Check both feet each day if possible.
Look at the soles and between the toes, using a mirror or another person’s help if needed.
Watch for redness, warmth, blisters, cracks, calluses, drainage, or a change in shape.
Avoid walking barefoot, including indoors.
Shoes and braces should be inspected for wear, rough seams, or objects inside.
New footwear may need to be introduced gradually and checked by a foot-care professional.
Calluses should not be cut at home, and over-the-counter corn removers can injure skin that has reduced sensation.
Every sign above is quoted from the sofidex article on Charcot foot. If you are not sure, err upward — it is always reasonable to be checked.