The \( B^0 \to K^{*0} \mu^+ \mu^- \) decay is mediated via the rare flavour-changing neutral current transition \( b \to s \mu^+ \mu^- \), and constitutes a sensitive probe for physics beyond the Standard Model (BSM). Previous LHCb measurements of the decay have shown interesting tensions with the SM predictions at the level of 3-4\(\sigma\). The theoretical interpretation of the anomalies is difficult due to the uncertainties in nonlocal SM contributions, such as charm-loops \( b \to s c \bar{c} \), which could mimic BSM effects through interference with the rare mode. A data-driven approach was adopted to constrain the size of the charm-loops and other nonlocal contributions to the \( B^0 \to K^{*0} \mu^+ \mu^- \) decay, in the first measurement to parameterize the full range of the dimuon invariant mass spectrum. Through the rescattering of \( B^0 \to K^{*0} \tau^+ \tau^- (\to \mu^+ \mu^-)\), the first direct measurement of the \( b \to s \tau^+ \tau^- \) coupling is also performed. The results are obtained using an integrated luminosity of 8.4 \(\mathrm{fb}^{-1}\) collected by the LHCb experiment during 2011-2012 (Run 1), and 2016-2018 (Run 2). Although the result of the nonlocal contributions is found to be larger than previously assumed in interpretations of previous measurements, the vector coupling is still shifted from the SM value.