Mometasone is classed as a potent topical corticosteroid. Topical corticosteroids are also referred to as topical steroids . Topical steroids are used in addition to moisturisers (emollients) for treating inflammatory skin conditions such as eczema and dermatitis . A topical steroid is used when patches of eczema or dermatitis flare up. Mometasone relieves the symptoms of a flare-up by reducing inflammation, itching and redness. It is not a cure for the condition, but it will help to relieve the symptoms. Short courses of mometasone may also be prescribed for the treatment of psoriasis for small areas such as the scalp, soles of the feet, or palms of the hands.
The obvious priority is immediate discontinuation of any further topical corticosteroid use. Protection and support of the impaired skin barrier is another priority. Eliminating harsh skin regimens or products will be necessary to minimize potential for further purpura or trauma, skin sensitivity, and potential infection. Steroid Atrophy   is often permanent, though if caught soon enough and the topical corticosteroid discontinued in time, the degree of damage may be arrested or slightly improve. However, while the accompanying Telangectasias may improve marginally, the Striae is permanent and irreversible. 
References: 1. Bikowski J, Pillai R, Shroot B. The position not the presence of the halogen in corticosteroids influences potency and side effects. J Drugs Dermatol . 2006;5(2):125-130. 2. Del Rosso J, Friedlander SF. Corticosteroids: options in the era of steroid-sparing therapy. J Am Acad Dermatol . 2005; 53(1 Suppl 1):s50-s58. 3. US Food and Drug Administration NDA 017765. Promius Pharma, LLC, Princeton, NJ: Aug 1977. 4. Rosenthal AL. Clocortolone pivalate: a paired comparison clinical trial of a new topical steroid in eczema/atopic dermatitis. Cutis . 1980;25(1):96-98. 5. Kircik LH. A study to assess the occlusivity and moisturization potential of three topical corticosteroid products using the skin trauma after razor shaving (STARS) bioassay. J Drugs Dermatol . 2014;13(5):582-585. 6. Cloderm [package insert]. Princeton, NJ: Promius Pharma, LLC; 2017.