Once you have hashimoto's, will you always have hashimoto's?

May be: Not necessarily, some people will go on remission the best way to know is by checking regularly your thyroid blood levels if your levels showed that you do required more medicine to balance the thyroid that could've that you are on remission.

Most likely.: You will probably continue to make antibodies that target your thyroid proteins for the rest of your life. If the antibodies are causing your thyroid to be underactive, this will usually persist, and will often progress to the point where your thyroid makes no thyroid hormone (so you may need higher doses of thyroid hormone over time). If there is pain or swelling, these usually do go away.