I had a small bump come up on thr right side as you describe. It was the presence of a lotion, ie sunscreen left on when i took an evening nap.
More likely making sure there is NO oils etc will stop the problem.
A sidenote. I love the Dreamwear but I dont see how a man or woman with short hair uses one.
I have long hair so I jusy ponytail it at night and slip the head strap under it to keep the strap from sliding up the back of my head.
If I were to cut my hair it wouldnt stay on three minutes before falling off.
Super tight is probably way too tight.
Also, try the different size cushions. It may just be rubbing in a certain area.
Ask your doctor for something to help heal the sores that you can use during he day and once healed, use a nasal gel like Ayr gel or a lanolish cream. (Found in baby isles in any drugstore.)
Cleaning with alcohol wipes may actually aggravate the issue, it caused skin irritation and problems for me.
Now I just fill the hand basin with warm water, lather up my hands with a block of ordinary bath soap, and then use the lather to wash the mask... haven't had any skin irritation since using that method.
I also wash the humidifier with either a liquid hand soap, or dish washing liquid, by hand in warm water, and then rinse thoroughly in cold running water before drying with a soft towel.
About once a month I put the headgear [minus the mask and frame] in a delicates mesh washing bag and put it through the washing machine with other clothes on a gentle wash cycle.
I have also put it through the clothes dryer, still in the mesh bag, with other clothes on a low heat drying cycle.
Use your own discretion for your own specific headgear to decide if your gear will survive this method with no ill effects.