Can a epi pen help during an asthma attack?

Depends: Epi pens are used in people who experience severe allergic reactions. The source of the allergy is not really important. If the asthma attack is the direct result of the allergic reaction it may be beneficial. However, "epi" is a non-specific "agonist" whereas your rescue inhaler is specific for the receptors in your lungs and would probably work better with fewer side effects.

Yes...but..: Some 4 decades ago something similar was the common 1st management for an attack. Drawbacks include the massive stimulation of the heart rate and elevation of blood pressure. It could be used in an emergency if an inhaler wasn't available, but the effects wear off in about 15 min. The person should be on their way to get needed care or it could get worse quickly.