Well you can't heal in a campaign afaik, But you should play single missions and generated missions enough so you have the best gear and experienced officers.

The campaigns are tough and it's best to go in at your best.

Originally posted by specter_origin:

I am new to the game, and so far I am enjoying the game apart from the healing mechanic in campaign. I have "Iron Man" off and all assault team is injured. What is the way out? is there no way to heal? a mod to heal or any workaround?
What is even more frustrating is how most of them are looking for few days to heal, I am that is kind of ridiculous.

Hi, campaigns are intended for a skilled and leveled squad and for an experienced player.

Regarding the health of our trooper during a campaign, if they are injured during one mission, you can side line them for the next one and use fresh trooper instead. Once the next mission is accomplished, they regain there full health.
If some members of the assault team are killed during a mission and you choose to continue, you loose them. To avoid that, you can choose to restart the mission, which reset the result of the last mission, the health of your trooper and keep those who have been killed alive.