This does not look like any shampoo residue and you should have taken steps to take care of it long time ago. This board is not a good place for such, seemingly advanced condition-deep yellow pigmented and large area. It might be fungus infection. You must see a physician. You can apply for Medicaid if eligible. Any local or city hospital has financial office that will apply it for you depending on income and if your state offers one. Be smart, and do search on Medicare if Florida offers one and find out the income cut off etc. Alternatively, call several hospitals in your area and ask them if they see patients on sliding income scale with reduced cash fee. Without insurance, the best bet would be to go to your local/city government hospital, not private ones, and make an appointment with a Physician. Visit the place, find out about their reduced cash fee which could be as low as $15 a visit. You will need to see the physician first who will refer you to the Specialist for further diagnosis. Where I am, the city hospitals are quite generous and charge only $15 or $20 from uninsured and with low income-the income whatever they declare and they do not verify or anything, just would put you in their reduced fee plan. My city also offers subsidized/free private insurance to low income residents where they can go to even private hospitals with almost no co-pay. But the income requirement is really low and if verifiable, then most residents do not qualify-but that's a different story. I would find out what the deal is in Miami by calling the city hotline. Also, if you have any issues, such as, you can not provide SS# or other identity documentation, then city owned hospital would be the best bet. In addition, there are also small clinics/medical centers that cater to uninsured for very low fee without asking much for their documentations.