I stopped using Rogaine after 29 days. Worried about long-term damage, should I be concerned? (Photos)

You need a formal evaluation to see what type of hair loss you may have. When you have hair loss, it's best to do a full hormonal workup for internal optimization, evaluate with a dermatoscope, consider scalp biopsies or scrapings to rule out any stress related, inflammatory, autoimmune or infectious causes of hair loss. In general, most people with early hair loss have telogen (stress related) and/or androgenetic (normal aging) and both can be treated with in office treatments like steroid injections, PRP/Acell, Exosomes and at home treatments like oral medications, oral vitamins like Viviscal, topical exfoliating sprays like Restorsea, and weekly growth factors like anteagemd. Though the exact mechanism of action of Rogaine/Minoxidil is not fully known, it is believed that it increased blood flow to the hair shafts thus causing thinner hairs to become thicker. Depending on your particular nature of hair loss, if you stop using Minoxidil, it will stop providing the increased blood flow and your hair may return to it's pre-treatment process, alternatively you may not lose any hair after stopping, though it has been reported to have increased hair loss after discontinuing Minoxidil. See an expert for an evaluation. If hair loss is significant it may requires hair transplant (follicular unit translation).

Minoxidil will be out of your body within a few weeks at most. It should not damage your normal hair or make it shed when you stop it.