What can I do about my creepy loose skin on my arms?

It would be helpful to see a photograph of what you are describing. It sounds like you would be well served by a brachioplasty, but you should see a board-certified plastic surgeon for an evaluation. You could get a better idea of what would be most appropriate for you.

Thanks for the question. Best to seek consultation with board-certified plastic surgeons who can demonstrate significant experience achieving the types of outcomes you will be pleased with. Learn about the pros/cons/possible risks/complications associated with the procedure as well. The arm lifting procedure is a great procedure to remove excess skin and adipose tissue of the upper arms. However, this procedure carries a major drawback: difficult scarring that may require scar revision (more so, in my experience, then other procedures).
I have tried placement of the resulting scars in the bicipital groove (between the biceps and triceps muscles) as well as a long the inferior–lower aspect of the upper arm. I have found higher patient satisfaction with the latter approach. If the excision can be planned such that the scar falls along the frontal aspect of the lower arm, then the scar may be visible only when the patient raises his/her arms.
As with many plastic surgical procedures, the planning of the incisions and resulting scar line is critical. However, even with attention to detail, the resulting scars may not be ideal and revisionary surgery is often necessary to improve the appearance (for example, the width) of the scars.
You may find the attached link, dedicated to arm lifting surgery concerns, helpful to you as you learn more. Best wishes as you work towards your goals.