The answer to this question depends on a few factors. One of the most important things to know is how long the heel pain has been going on. Plantar fasciitis that has gone untreated for months can take months to resolve. The longer that your body tries to compensate for this injury, the more scar tissue can build up, and the more complicated the condition becomes to treat. Heel pain that is addressed within 1-2 weeks of its onset has the potential to resolve with treatment within 1 week.
Other factors at play include the age of the person with heel pain and, of course, if there are other associated conditions. Other conditions that may be associated with plantar fasciitis include bursitis of the heel, which is a condition in which there is inflammation or swelling of a bursa (fluid filled sac) at the bottom of the heel. In addition, heel pain may also be due to underlying plantar fascia tears. In instances where the plantar fascia has torn, it requires protection and rest to heal, just like any other sprain.
Heel pain that has been present and/or worsening for more than 1 week may not even be plantar fasciitis! This is why it is critical to have your heel pain assessed by your foot doctor.