Rub your hands on a stainless steel utensil (spoon, etc) under running water. This also works for other strong smells like fish and onion.

Press and roll the lemon against a table or kitchen counter. This will soften the lemon and you’ll be able to squeeze more juice.

Put a rubber band around the lid to have a good grip. You’ll find it very easy to open the jar now. A rubber glove can also be used.