I would hope you have a GHIC card rather than an EHIC, since the EHICs ran out a while back (unless you are an EU citizen living in the UK), but anyway, yes, you can go to a French GP and they will do the necessary, as EHIC/GHIC covers both emergency and ongoing care.
However, with the French system you may have to pay up-front and then claim back. The deal with EHIC/GHIC is not that you get free treatment, it's that you get the same deal as local people. The standard price of a GP visit in France is €30, which the French state system reimburses at 70% (€21) - most French people have top-up insurance to cover €7 of the remaining €9 (it's illegal to reimburse the last €2, to discourage people from visiting 10 GPs until one caves in and gives them antibiotics for a cold). I'm not sure how you go about getting reimbursed but the NHS website probably has it, and if not look up NHS Overseas Healthcare Services and call them.
I think the first place I would go in your case is a pharmacy. They might just be able to do the dressing there, and if not they will point you to a nearby doctor or clinic. In most towns there are no waiting lists, but you may have to sit in a waiting room for a couple of hours.
If you need help with communicating then I thoroughly recommend the app/website called DeepL. It is vastly better than Google Translate and it's free for up to about 700 words at a time.