I Visited My GP Tuesday Because A Red Area Appeared

I visited my GP Tuesday because a red area appeared under my leather orthotic and prescribed me betamethasone Valerie to put on twice a day since starting this ointment my whole arm and hand have accelerated the infection which now covers my lower left arm and down my little finger and thumb on my hand this can only be triggered from an allergy to this ointment and is very itchy and original area was hot is this something more serious