I started using hydrocortisone 2.5% and it stings a little bit should i go to a 1% hydrocortisone cream instead? i have sensitive skin and vulvar eczema?

Slight stinging at the time of application probably has nothing to do with the hydrocortisone -- more likely related to other ingredients in the cream or ointment. However, probably you shouldn't be on the stronger version if the 1% cream is effective; and usually not on the stronger type unless prescribed by a doctor. In that case, ask the doc. Good luck.