Thank you for your query.
injections are given to enhance the lung maturity of the babies, since with twins you run the risk of preterm delivery.
You could be having a rash in reaction to the steroid injections, as it is very common.
However, it could be any other rash - for example, allergy, contact dermatitis
, viral infections etc.
You need to consult your doctor / dermatologist
before embarking on any medication , particularly considering the high risk nature of your pregnancy