Itching on your outer and inner labia that worsens around periods, with a little whitish residue, usually points to vulval skin irritation or a mild yeast-type overgrowth. It's not something to treat with a cream picked over chat, since the wrong one can make irritation worse.
Next Steps
Wear breathable cotton underwear and avoid scented soaps or wipes in that area. Rinse with plain water after urinating instead of scratching or scrubbing. If it doesn't settle in a week, see a gynaecologist for an exam and a quick swab test.
Health Tips
See a gynaecologist sooner if you notice a strong odour, a change in discharge colour, or pain during sex.