Chewbacca
Please have a look at our PIP MR & Appeal guide for details of the MR process.
You should request a copy of the assessment report to better understand how they have come to their Decision.
Whilst it is not impossible, it is unlikely that the DWP will revise the current Decision if you do not show them why you meet the criteria for PIP Daily Living and/or Mobility, so you need to give some thought as to how you have already presented your day to problems and how you might explain them in more detail to take account of the DMs response.
Although you have already requested an MR I would confirm the request in writing to ensure that it does not get lost in the DWP systems.
If you have any specific questions then please reply to this post and we will do our best to help.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems