Scalded cats fear even cold water.

One bad burn teaches a lesson wider than the event that caused it. After real harm, the mind stops sorting carefully and begins flinching at anything resembling the thing that hurt. That reflex is not foolish; it kept you safe once, and it is still trying to. The cost is that it also keeps you away from what was never dangerous at all.

When something makes you pull back, ask quietly whether this particular thing has ever hurt you, or only resembles what did. You do not have to override the flinch. Testing one small safe version of it is usually enough to begin teaching the difference.